Table of Contents E65 Seat, Mirror & Steering Column Functions Subject Page Introduction .4 Front Seat Versions.4 Rear Seat Versions.4 Exterior Rearview Mirrors .5 Steering Column Adjustment .5 System Interface .7 Components.7 Component Overview.7 Switch Block, Driver and Passenger .8 Switch Operation .8 Center Console Control Center (BZM) .9 Seat Modules (SMFA, SMBF).9 Principle of Operation.10 Seat Memory .10 Memory Preset buttons.11 Programming.12 Calling Up Memory Positions.12 Seat bleating.13 Activation of Heating Areas .15 Operation .15 Balance Control .16 Seat Ventilation .17 Operation .18 Lumbar Support.19 Operation .19 Active Seat .20 Functional Description.21 Exterior Rearview Mirrors.22 Horizontal and Vertical Mirror Adjustment.23 Mirror Heating.23 Automatic Curb View.24 Mirror Memory .24 Electro-chromatic Exterior Rearview Mirrors.25 Under-voltage Deactivation.25 Initial Print Date: 12/04 Revision Date: Subject Page Electric Steering-Column Adjustment .26 Automatic Entry .27 Soft Stop .27 Steering-Column Memory .27 Steering Wheel Heating.28 Diagnosis of Steering Wheel Heating.28 E65 Seat, Mirror & Steering Column Functions Model: E65/E66 Production: All ■Biiermis After completion of this module you will be able to: • Locate and identify seat, mirror and steering column components • Diagnose systems related to seat, mirror and steering column systems • Understand the operation of seat, mirror and steering column systems 3 E65 Seat, Mirror and Steering Column Functions Introduction The E65 can be equipped with several different seat versions. Front Seat Versions The front seats come in 2 versions: • Standard: 14 way Basic Seat (12 way passenger), electrically adjustable with memo¬ ry and 4 way lumbar. The head-restraints of the basic seat are not separately adjustable; they are controlled by a cable mechanism automatically when the seat is moved forward or backwards. This allows the head restraint to always be in the opti¬ mum position for safety. Seat heating is available as a stand alone option or part of the cold weather package. • Optional active seat package: 20 way Comfort Seat with memory, 4 way lumbar, seat ventilation and active seat feature. The head restraints are controlled automatically with forward/backward movement of the seat. However, positioning is done electri¬ cally and it allows separate electric adjustment of the head restraint. Seat heating is also available for the comfort seat as a stand alone option or part of the cold weather package. Rear Seat Versions The E65 comes equipped only with the basic rear seat. Head restraint adjustment is automatic if equipped with the rear safety package. The rear seats will have optional rear heating avail¬ able as part of the cold weather package. There will be a comfort seat with memory for the rear when the E66 745Li is introduced later. 4 E65 Seat, Mirror and Steering Column Functions Exterior Rearview Mirrors The exterior rearview mirrors are electrical¬ ly adjustable and heated. They are also equipped with electro-chromatic auto dimming and are part of the seat memory system. Steering Column Adjustment Steering-column adjustment is fully elec¬ tric. System Overview Basic Seat Lumbar components are not shown Index Explanation Index Explanation BZM Center Console Control Center SLV Longitudinal seat adjustment CON Controller SHV Seat height adjustment CAS Car Access System SNV Seat inclination adjustment SMFA Seat module, driver’s side LNV Backrest inclination adjustment SMBF Seat module, passenger side 1 16-pin ribbon cable K-CAN-S K-CAN System 2 12-pin ribbon cable K-CAN-P K-CAN periphery 3 12-pin ribbon cable KL 30 Terminal 30 4 14-pin ribbon cable 5 E65 Seat, Mirror and Steering Column Functions System Overview Comfort Seat an Lumbar, ventilation and active seat components are not shown. K CANS CAS ' JL Index Explanation Index Explanation BZM Center Console Control Center K-CAN-S K-CAN System CON Controller K-CAN-P K-CAN periphery CAS Car Access System 1 16-pin ribbon cable CD Control Display 2 12-pin ribbon cable SMFA Seat module, driver’s side 3 12-pin ribbon cable SMBF Seat module, passenger side 4 14-pin ribbon cable KL 30 Terminal 30 5 14-pin ribbon cable SLV Longitudinal seat adjustment LNV Backrest inclination adjustment SHV Seat height adjustment LBV Backrest width adjustment SNV Seat inclination adjustment LKV Backrest head adjustment STV Seat cushion adjustment KHV Head restraint height adjustment SBV Seat width adjustment 6 E65 Seat, Mirror and Steering Column Functions System Interface The variety of comfort functions are distributed to various control units. Communication between the relevant control units is conducted byway of the bus, especially to carry out the memory functions. CAS SMI A SMBF TMFAT TMBFT TM FATH TM BFTH SMFAH SMBFH HKL PM Al 1M PDC RDC CIM LM DWA IHKA CON BZM RLS SHD SH BZMF I Kombi m ASK in TEL I CD L CDC 1 AVT 1 LOGIC 7 I svs D-BUS SZL SFZ SASL SASR ARS EMF STVL SSFA SIM STVR DME GRS SSBF EGS DSC SBSI SBSR NAV SSH EDC-K K-CAN P K-CAN S MOST byteflight PT-CAN Components Component Overview • Switch block, driver and passenger side • Center console Control Center (BZM) • Car Access System (CAS as gateway)) • Seat module, driver and passenger side (SMFA/SMBF) • Seat-adjusting motors (memory seats include hall sensors for position detecting) • Air pump, bladders and solenoids for lumbar support Additional eguipment for comfort seats: • Active seat unit per seat • 9 smart fans per seat for seat ventilation Optional eguipment for basic or comfort seats: • Seat heating elements 7 E65 Seat, Mirror and Steering Column Functions Switch Block, Driver and Passenger The forward switch assembly contains a control knob and menu buttons in the shape of a seat for function selection. The rearward switch assembly contains the memory function buttons and possi- Control bly three more features: knob • Seat heating control The controls for the driver and passenger seat have been relocated from the seat side panel and are now part of the center console. The switch block consists of two separate switch assemblies. Menu Memory and auxiliary Buttons function buttons • Seat ventilation control • Active seat control LEDs indicate the operating status of each particular seat auxiliary function. The adjustment reguest is transmitted from the switch block via ribbon cables to be processed by the BZM. Switch Operation The control knob is a “joystick” that can be pushed or rotated. It is used to control whichever portion of the seat has been selected using the menu buttons. The operation of the memory and auxiliary seat function buttons is discussed separately in “Principle of Operation”. 1. Selection button for lumbar and back-width adjustment (comfort seat). 2. Selection button for shoulder tilting (comfort seat), backrest inclination and head-restraint height (comfort seat) adjustment. 3. Selection button for forward/back (longitudinal) seat height and backrest inclination adjustment. 4. Seat cushion tilting, thigh support. Note: The selected menu button lights up to confirm the request. 8 E65 Seat, Mirror and Steering Column Functions Center Console Control Center (BZM) The BZM is located in the center console directly below the Controller. The BZM inter¬ prets the signals from the seat blocks and makes the message available to the CAS on the K-CAN-System. The CAS as the gateway, forwards the mes¬ sages to the K-CAN-P where they can be received by the seat modules. Seat Modules (SMFA, SMBF) The Seat Modules are located below the driver’s and passenger’s seat next to the seat satellites. They are clipped into a plastic carri¬ er. The Seat Modules have 10 con¬ nectors. Both the driver’s and passenger’s seat modules are identical. The mod¬ ules are recognized by an additional ground on the drivers side module at pin 2 ofX275 (8-pin). The seat module activates the seat-motors directly via final stages. Up to 3 motors may be run simultaneously. The total running time of each adjusting motor is monitored in order to prevent thermal overloading. The seats eguipped with memory use motors with integral hall sensors for position detecting. The position of the mechanical stops is stored on initial operation. In the following adjustments, the seat stops before this position is reached (soft stop). (The soft stop can be overridden if the seat is operated in the same direc¬ tion immediately afterwards). 9 E65 Seat, Mirror and Steering Column Functions In the comfort seat, the 4 main seat adjustments are equipped with a smooth startup: • SLV: Longitudinal seat adjustment(forward/backward) • SNV: Seat-inclination adjustment • SHV: Seat-height adjustment • LNV: Backrest-inclination adjustment Principle of Operation Seat Memory The seat memory offers the opportunity of storing up to 3 different positions (2 memory presets and “last position used”) for every Remote Control used. This means that if 4 Remote Controls have been assigned to the vehicle, up to 12 differ¬ ent positions can be stored in the individual seat module. Availability of these 12 positions depends on whether Key Memory is set to “active” or “not active”. With Key Memory set to “not active”, only 3 memory positions are available. They are assigned to the vehicle irrelevant of the Remote Control being used. With Key Memory set to “active”, memory presets stored are assigned to the Remote Control that is currently being identified (memory preset 1 and 2 and the “last position used”). The number of stored positions then becomes 3 X the number of remote con¬ trols assigned up to a maximum of 4 (12 positions). Remote Control 1 Remote Control 2 Remote Control 3 Remote Control 4 1 2 3 4 5 6 7 8 9 10 11 12 Key Mem. 1 Mem. 2 Key Mem.1 Mem.2 Key Mem. 1 Mem. 2 Key Mem. 1 Mem. 2 The following components are required for the seat-memory function: • Memory buttons, driver’s and passenger’s • Center Console Control Center (BZM) • Car Access System (CAS) • Seat module, driver and passenger (SMFA/SMBF) • Seat-adjusting motors with a Hall sensor 10 E65 Seat, Mirror and Steering Column Functions The SMFA/SMBF requires information from the CAS in order to execute the stored seat positions: Remote Control number and memory buttons (from the BZM). • The information is sent from the CAS via the K-CAN P to the seat module. • The seat-adjusting motors are then activated accordingly. When using the Remote Control to unlock the vehicle, the seat automatically moves to the last position used for that Remote Control. If an unlocked car is entered and no button of the Remote Control is pressed, the seat moves to the last position stored once the Remote control is identified by the CAS. At the same time, the CAS sends the same information to: • The front door modules for the mirror-memory position. • The CIM (Chassis Integration Module) for the steering column memory positions. Memory Preset buttons The memory buttons are integrated in the memory/auxiliary function switch block (behind the adjusting-switch block) and consist of: • Pad with 3 buttons (position buttons 1 and 2 and a memory storage button). • Indicator LED in memory storage button for memory readiness. Depending on the special equipment fitted, the buttons for the following functions can be integrated in the switch block: - Seat heating - Seat ventilation - Active seat The status of the memory button is communi¬ cated to the relevant seat module over the bus system. Signal path: Button > ribbon cable > BZM > K-CAN S > CAS > K-CAN P > SMFA or SMBF. The position of the lumbar support cannot be stored. 11 E65 Seat, Mirror and Steering Column Functions Programming Programming of seat positions is only possible from terminal R "on". The following operating steps must be performed in order to store a seat position: • Press memory button "M": The memory button lights up to acknowledge program¬ ming readiness. • Press position button: adoption of current position of seat, steering column and side mirrors. • Programming readiness is deactivated if no position button is pressed within 7 sec¬ onds while it is activated. The function indicator is deactivated. • Programming readiness is also deactivated when the memory button is pressed again. • If no personalization key is recognized, the programming function is not available when the key memory is activated. Calling Up Memory Positions There are 2 operating modes for calling up stored positions on the driver's seat: • One touch mode: touching the desired position button moves the seat automatically up to the end setting of the stored positions. The one-touch function is only possi¬ ble with terminal 15 "off" to eliminate any safety hazard caused by accidental touch¬ ing of the button. • Continuous hold mode: the seat moves only as long as the desired position button is continuously pressed. The motors are shut down immediately if the button is released before the target position is reached. Pressing the position button again resumes the positioning up to the end setting of the stored position (target position). 12 E65 Seat, Mirror and Steering Column Functions Seat Heating Seat heating is an option or part of the cold weather package. The following components are reguired for the seat-heating function: • Switch block, auxiliary functions, driver and passenger • BZM • Controller (CON) • Control display (CD) • Car Access System (CAS) • Seat module, driver and passenger (SMFA/SMBF) • 2 rapid heating elements per seat • 2 regular heating elements areas per seat • 4 temperature sensors 13 E65 Seat, Mirror and Steering Column Functions The switch block contains the control button and 3 orange LEDs. The LEDs indicate the various heating stages. The signals for operating the seat heating are transmitted over the buses. Signal path: Button > 14-pin ribbon cable > BZM > K-CAN S > CAS > K-CAN P > SMFAorSMBF. The seat modules incorporate activation and control of seat heating. Each seat has 4 heating elements, which are sewn into the seat cover: • 1 rapid heating element in each inner seat cushion area and in inner backrest area. • 1 residual heating element in each outer seat cushion area and in outer backrest area. Each heating element is monitored by an NTC temperature sensor. 1. Rapid heating element 2. Regular heating element 3. Backrest cover 4. Seat cushion cover 14 E65 Seat, Mirror and Steering Column Functions Activation of Heating Areas When the seat heating is turned on, the rapid heating elements are activated first in order to heat up the seats guickly. After the initial rapid heating, the regular heating areas are activated in order to ensure a uniform distribution of temperature in the seat. Seat Heating Off On Rapid Heating Regular Heating Rapid Heating element Regular Heating element Activation of all the heating elements is PWM so that an established current intensity is not exceeded during regular heating. The duty factor is dependent on the selected heat¬ ing stage, the ON period and the heating-area temperatures. The function indicators (LEDs) of the seat heating remain on if the heating is briefly deac¬ tivated (e.g. during seat adjustment or by power management). Operation The seat heating can be turned on from terminal 15 and the engine running. Stage 3 (maximum temperature) is activated when the button is pressed for the first time. Each subseguent pressing of the button selects the next stage lower or "off". The seat heating is turned off if the button is pressed for longer than 1.2 seconds. The seat heating remains in stand-by (service station feature) for 15 minutes after terminal 15 is switched off. 15 E65 Seat, Mirror and Steering Column Functions Balance Control The vehicle occupant can use a balance controller to adjust a temperature differential between the seat cushion and the backrest up to +/- 3°C. The balance controller can be called up in the Control Display and is set with the Controller. This setting remains permanently stored specifically to each Remote Control (Key Memory activated). For balance control, switch to the Climate menu and call up seat heating from the second page. Select driver's or passenger seat. 1. Select second page from climate menu 2. Select seat heating 3. Select left or right seat 4. Rotate controller to vary the ratio of heat between backrest and cushion. >Z< nlDD D2 Privat jjjj TMC Standheiz. Links j Sitzheiz. rechts 1 X JJ Links Rechts U 1 20,0°C SS Auto ANTENNE Auto % 20,0°C Kecnis/LinKS ▼ auto rrog r"V Oben Mitte Unten Individuell 0 Links Speichern illinium iiiiuiiit D 1 20,0°C SS Auto ■J MD 03 Auto * 20,0°C The driver's or passenger seat can be selected in this menu. Turn the Controller to vary the balance of heat output between the seat surface and the backrest. This change in balance is indicated by a red/white coloring of the seats in the Control Display. 16 E65 Seat, Mirror and Steering Column Functions Seat Ventilation The seat ventilation feature of the comfort seat allows the front seat occupants to cool the seat cushion and backrest. The following components are required for the seat ventilation function: • Switch block, auxiliary functions, driver and passenger • BZM • Car Access System (CAS) • Seat module, driver and passenger (SMFA/SMBF) • 9 smart ventilation fans per seat 17 E65 Seat, Mirror and Steering Column Functions The auxiliary function switch block contains the control button and 3 LEDs for displaying the ventilation stage. The signals for operating the seat ventilation are transmitted over the buses. Signal path: Switch block > 14-pin ribbon cable > BZM > K-CAN S > CAS > K-CAN P > SMFA orSMBF. The relevant seat module activates and monitors the fans. The fans: • Are activated by the seat modules supplying voltage. • Can be activated separately for back rest and seat cushion. • Can be operated in 2 speed stages (high and low) via a control/diagno¬ sis line. • Indicate possible jamming for diag¬ nosis over the control/diagnosis line. Fault code only identifies whether the defective fan is in the backrest or the cushion it does not identify individual fan motors. Operation The seat ventilation can be turned on from KL 15 "on" and the engine running. Seat ventilation has 3 stages but only two fan speeds: • Stage 3: High speed backrest, high speed cushion (seat bottom) • Stage 2: low speed backrest, high speed cushion • Stage 1: low speed backrest, low speed cushion Stage 3 is activated when the button is pressed for the first time. Each subsequent pressing of the button selects the next stage lower or "off". The seat ventilation is turned off if the button is pressed for longer than 1.2 seconds. The system switches down automatically from stage 3 to stage 2 after an running time of 15 minutes. The ventilation remains in stand-by for 15 minutes after KL R off is received. 18 E65 Seat, Mirror and Steering Column Functions Lumbar Support Both seat versions are available with pneumatic lumbar adjustment as standard equip¬ ment. The following components are required for the lumbar support function: • Switch block, auxiliary functions, driver and passenger • BZM • Car Access System (CAS) • Seat module, driver and passenger (SMFA/SMBF) • 2 inflatable air chambers (bladders) and 2 solenoids per seat • 1 air pump per seat Operation Lumbar adjustment is performed by 2 inflatable chambers (air bladders) in the backrest. The air chambers are inflated and deflated by 2 solenoid valves. The air pump delivers the required air pressure. The air pump and the actuators are activated by the seat module based on the com¬ mands from the seat switch block. The signals for operating the lumbar support are transmitted over the buses. Signal path: Switch block > 12-pin ribbon cable > BZM > K-CAN S > CAS > K-CAN P > SMFA orSMBF. 19 E65 Seat, Mirror and Steering Column Functions Active Seat The active seat was introduced for the first time in the E38 for model year '99. The active seats in the E65 have been adapted to the E65 electrical system. The active seats relieve the back muscles and spinal column on longer journeys. The seat cushion of the active seat is moved up and down in stages. For safety reasons, the active seat is paused when the vehicle is cornering. The following components are required for the active seat function: • Switch block, auxiliary functions, driver and passenger • BZM • Car Access System (CAS) • Seat module, driver and passenger (SMFA/SMBF) • 1 active seat unit per seat 20 E65 Seat, Mirror and Steering Column Functions The signals for operating the active seat are transmitted over the buses. Signal path: Switch block, auxiliary functions, active seat > 14-pin ribbon cable > BZM > K-CAN S > CAS > K-CAN P > SMFA or SMBF. Functional Description The system is filled with a glycol fluid. This fluid is pumped alternately into the left and right fluid bags (by reversing the direction of pump rotation). The following components are required for the active-seat function: • FHydraulic pump: the hydraulic-pump motor is activated with alternating polarity by semiconductors in the seat module. • Flail sensor: a Hall sensor records the revolutions of the hydraulic-pump motor. The motor function is monitored with this signal. • Solenoid valve: the solenoid valve is installed between the two fluid bags and opens and closes the delivery to the fluid bags. The valve is activated by semiconductors in the seat module. The solenoid valve is closed when the system is deactivated and in the intervals between the adjustments. In order not to irritate the driver when cornering fast, the operational sequence of the active seat is stopped immediately at high transversal acceleration: the solenoid valve remains closed from a specific transversal vehicle acceleration. The yaw-rate sensor telegrams the transversal- acceleration signal via the bus system. • Vacuum switch: a vacuum switch is installed in each of the fluid bags. These switch¬ es identify the extent to which the fluid bags are drained. In the event of a fault, the system stops or holds in order to avoid further damage. 21 E65 Seat, Mirror and Steering Column Functions Exterior Rearview Mirrors 2 electric rearview mirrors are fitted on the driver's and passenger doors of the E65. They are activated by the front door modules. All the mirror functions are controlled by the buttons in the switch block in the driver's door. The mirrors are directly controlled by the associated door module. The following functions are possible: • Horizontal and vertical mirror adjustment • Mirror heating • Automatic curb view • Mirror memory • Electro-chromatic • Under-voltage deactivation 22 E65 Seat, Mirror and Steering Column Functions Horizontal and Vertical Mirror Adjustment Both the exterior mirrors can be moved in the horizontal and vertical directions. However, they can only be adjusted in each case in one direction (horizontal/vertical). Each exterior mirror accommodates 2 adjust¬ ing motors: one motor for each adjusting direction. Potentiometers are fitted for posi¬ tion detection. A common control pad for both exterior mir¬ rors is located in the driver's door. The driver uses a slide switch to select between the two mirrors (right/left). Mirror Heating The function of the mirror heating is automatically controlled. The mirror heating is supplied via PWM signal. The current output is dependent on outside temperature and wiper operation. The outside temperature and wiper operation are delivered via the K-CAN. Temperature in Celsius <-10 -10 to 5 5 to 15 15 to 25 25 to 35 >35 On period (Percentage) 100% 100% 75% 25% 0% 0% On period with wiper actuation (Percentage) 100% 100% 75% 50% 25% 0% The heat output is increased in wiper mode in order to make any raindrops on the mirrors evaporate. When the wiper is deactivated, the higher percentage ON period remains active for a fur¬ ther 5 minutes. The mirror heating is operational from terminal 15 "on". It is deactivated with terminal 50 "on" (load deactivation during the starting seguence). The mirror heating is deactivated with priority 4, 5 and 6 for the function "Optimum charging of Power Module" (see Power Management chapter). • Cut-off voltage: 10.8V • Cut-in voltage: 11.6V 23 E65 Seat, Mirror and Steering Column Functions Automatic Curb View When the vehicle is being reversed, the passenger mirror is moved downward in order to provide a better view of the curb. Conditions needed are: • The exterior-mirror selector switch for operating the driver's mirror is selected. • Terminal 15 "on" • Reverse gear is selected Signal path: EGS - PT-CAN - ZGM - K-CAN S - CAS - K-CAN P - door module. • Delay time: 1 second after selection of reverse gear (in order to avoid unnecessary activation of passenger mirror when reverse gear is accidentally selected). The passenger exterior mirror immediately reassumes its original position: • After the reverse gear has been deselected • or with terminal 15 "off". Manual mirror adjustment is disabled until the mirror reaches its initial position. Mirror Memory The mirror-memory function is part of the seat-memory function. The current mirror set¬ tings on the driver and passenger sides can be stored or mirror settings already stored can be re-called using the memory buttons in the vehicle and the Key-Memory function. The memory positions are stored in the driver's/passenger’s door modules. The potentiometers for position detection are supplied by the door modules with a volt¬ age of 5 V. The potentiometers are deactivated in sleep mode. The various mirror-adjustments have different priorities. • Manual mirror adjustment has priority over all other mirror adjustments. Manual mir¬ ror adjustment interrupts any memory adjustment. • Mirror adjustment by means of the buttons of the memory function has priority over mirror adjustment by means of the Key Memory: A mirror activation in progress which has been initiated by the Key Memory is cancelled when the memory buttons are operated. 24 E65 Seat, Mirror and Steering Column Functions Electro-chromatic Exterior Rearview Mirrors Electro-chromatic exterior rearview mirrors ensure that the driver is not dazzled by the headlights of vehicles from behind. The exterior mirrors are automatically dimmed when a light source coming from the rear is detected. The sensor and control electronics for this function are integrated in the inside rearview mirror. • A photo sensor in the inside rearview mirror measures the amount of light coming from the rear of the vehicle as opposed to the front. • The control electronics calculates the amount of dimming required for this incidence of light. Stronger or weaker dimming of the exterior mirrors is performed depending on the degree of potential dazzling. The control signals are transmitted from the inside rearview mirror via the front door mod¬ ules to the exterior mirrors. Under-voltage Deactivation Under-voltage deactivation ensures that primary electrical-system functions take priority over the mirror functions. The supply voltage is monitored locally in the door modules. All the mirror functions are disabled if the supply voltage drops below 8.5 V. Once the voltage has dropped below this limit, the mirror functions are not available again until system voltage increases over 9 V. 25 E65 Seat, Mirror and Steering Column Functions Electric Steering-Column Adjustment The electrically adjustable steering column is adjusted (inclination and length) with the steering-column adjusting switch on the left side of the steering-column cover. Electric adjustment of the steering column is effected by the Chassis Integration Module (CIM). The CIM controls the motor gearbox unit for adjustment. The motors are activated internally by a power semiconductor. The steering column is moved into the upmost position for entry and exit purposes (automatic entry facility). 26 E65 Seat, Mirror and Steering Column Functions Automatic Entry The electrically adjustable steering column is moved into the upper-most position for entry and exit purposes. The automatic entry facility is activated when: • Terminal 15 "off" and terminal R "off". • Terminal 15 "off" while driver's door is open. • Driver's door is opened after terminal 15 "off", also when terminal R is still activated. The automatic entry is deactivated when terminal 15 is re-activated; the return position is approached. Automatic operation stops if the control switch for steering-column adjust¬ ment is operated during automatic entry. The previous return position is overwritten if automatic entry is interrupted by operation of the steering-column adjustment control switch. The return position is retained if while the automatic entry is active, the control switch inputs: "steering column up" (towards headliner) or "steering column forward" (towards instrument cluster) are operated. If the memory is called up while automatic entry is active, the memory steering-column position is assumed only after the automatic entry has been completed. The normal return position is substituted by the called-up memory position. Soft Stop If the steering column reaches a mechanical stop during adjustment, this position is per¬ manently stored. Starting out from this value, the adjustment travel for future adjustments is restricted to eliminate any future mechanical blocking. This soft stop can be manually overridden if the column is operated in the same direction immediately afterwards. Steering-Column Memory A Hall sensor is fitted in each of the adjusting motors. The Hall sensors record the steer¬ ing-column position for the memory functions. 2 different positions can be stored by means of the seat-memory buttons in the switch block. The memory positions are stored in the driver's seat module (SMFA). Automatic opera¬ tion stops if the switch for steering-column adjustment is operated during activation of the memory steering-column position. 27 E65 Seat, Mirror and Steering Column Functions Steering Wheel Heating The steering wheel heating is available as an option or as part of the cold weather package. It is operational from terminal 15 "on". It is activated and deactivated by pressing the but¬ ton on the left side of the steering-column cover. The LED indicator light in the button illuminates when the steering wheel heating is activated. The temperature in the steering wheel is monitored by a sensor and maintained at 36°C. The control electronics are in the SZL. The load current is passed on by the coil spring and the steering wheel electronics module. Index Explanation Index Explanation S3 Control Button NTC Temperature sensor SZL Steering column switch center LHZ Steering wheel heating WF Coil spring (contact ring) LSE Steering column electronics LRE Steering wheel electronics Diagnosis of Steering Wheel Heating In the event of a fault, the steering wheel heating (LHZ) can no longer be activated (if the fault is currently present). Faults can only be diagnosed after terminal 15 "on" and an attempt to activate the steering wheel heating has been made. The following fault mem¬ ory entries are available to diagnose the steering-wheel heating: • Steering-wheel heating, heating mat, short circuit to terminal 31 • Steering-wheel heating, heating mat, short circuit to terminal 30 • Steering-wheel heating, temperature sensor faulty The resistance value of the temperature sensor can be read out in the Diagnosis Reguest: "LHZ status". 28 E65 Seat, Mirror and Steering Column Functions Classroom Exercise - Review Questions Which control unit is responsible for converting the seat switch signals into bus telegrams and broadcasting them over the bus system? Where is this control unit located? Up to how many memory positions may be stored in the seat modules? What needs to set in VKM before all the possible memory locations can be stored? What are the differences in the way seat heating operates and is controlled compared to the previous model (E38)? Why are the fan motors of the ventilated seats referred to as “smart fans”? Where are the memory positions of the exterior rearview mirrors and the steering column stored? 29 E65 Seat, Mirror and Steering Column Functions