Part 3
When the engine is started and the AUC function activated, fresh-air mode is always selected for approx. 40 seconds due to the warming phase of the AUC sensor.
Program for preventing condensation on the window surfaces (IHKA only)
The following conditions must be satisfied for measures against condensation on the windscreen to be effected:
- Engine running
and
- The IHKA must be in automatic mode
The IHKA control unit evaluates condensation sensor signal (humidity). If condensation on the windscreen is imminent, the following measures are initiated in sequence to prevent condensation from forming.
If a measure proves to be ineffective, the next measure is initiated.
Once successful, the measures previously performed are reversed step-by-step in reverse order.
Measures if the windscreen threatens to mist over:
- Open defrost flaps further
- Switch from air recirculation/AUC/automatic air-recirculation mode
to partial fresh-air mode
- Switch from partially fresh air in air-recirculation/AUC/automatic air-recirculation mode to fresh air
- Increase air volume with the blower
- Reduce air volume for the footwell
- Increase desired temperature value
- Reduce air volume for the footwell
- Increase desired temperature value
Central kinematics actuation (IHR, IHKR only)
The air distribution flap motor has the task of setting the air distribution over a cam disc. The air distribution flap motor has no way of recognising the actual position. To allow the cam disc to be unambiguously positioned despite this, there are two cams of different widths on the cam disc. The microswitch signals to the IHR/IHKR control unit when the cams pass. This mechanism ensures that the cam disc is reliably and promptly positioned.
Convertible program (E93 only)
The convertible program is activated in the factory. (this factory setting can be deactivated in the "Personal Profile".)
Switch-on conditions:
- Terminal 15 ON
- Convertible top open
The convertible program comprises the following functions:
- The condensation sensor is switched off
- The blower speed increases with increasing road speed
- Air distribution is switched to the upper body and head, airflow to the footwell is throttled.
- Dynamic pressure compensation is changed, i.e. as road speed increases, the volume of air fed into the vehicle through the fresh air grille increases.
- Solar sensor control variables are changed
When the convertible top is open, the solar sensor evaluates the surrounding brightness (darkness to intense sunshine) more strongly. For this reason, the solar sensor has a stronger effect on the IHKA controls when the convertible top is open.
In the convertible program, the blower speed can be changed manually at the IHKA controls. The automatic flap control remains active (no change to flap position).
If the convertible program is active and the flap positions are changed with the CID and controller, the convertible program will be deactivated. This means that manual settings will be assumed, unchanged settings will revert to those that the air-conditioning system had before the convertible top was closed.
The convertible program can be completely reactivated by pressing the AUTO button.
Independent heater (option 536)
The independent heating function is activated either via the Central Information Display (CID) or via Telestart (through the Car Access System (CAS)). There are 2 ways of switching the system on via the CID:
Direct operation or programming using the timer.
[for further information, please refer to SI Technology (SBT) 64 01 05 135]
Automatic rear air conditioning (option 4NB, E70 only)
The automatic rear air conditioning provides for separate temperature and blower settings for the left and right sides in the 2nd row of seats.
[more ...]
Additional heating/ventilation for 3rd row of seats (option 4NC, E70 only)
A rear compartment blower draws air in under the seats in the 3rd row of seats and blows it out through the ventilation air outlet between the seats in the 3rd row of seats.
[more ...]
Seat heating and active seat ventilation (E70 only)
Seat heating and active seat ventilation in front
If the seat heating/active seat ventilation button is pressed, the IHKA control unit sends the status as a K-CAN message.
Depending on the equipment version of the seat, the message is received either by the seat modules or by the Junction Box electronics (JBE).
- Message direct to the seat modules:
The seat heating and the active seat ventilation are actuated by the respective seat module according to the control logic at the IHKA control panel.
- Message via Junction Box electronics:
The Junction Box electronics transmits a message to the seat modules in the form of a pulse-width modulated signal (PWM signal). The seat heating is actuated by the respective seat module according to the control logic at the IHKA control panel.
If the energy management system requires a reduction in output, the heater and blower output may be reduced in 3 stages or switched off completely:
1. Heating and blower output are reduced from level 3 to level 2
2. Heating and blower output are reduced to 50 percent of level 2
3. Seat heating and active seat ventilation are switched off
Seat heating in rear without automatic rear air conditioning
When the seat heating switch for the rear is pressed (2 levels), the seat heating is directly actuated.
If the energy management system requires a reduction in output, the seat heating in the rear may be switched off by a relief relay.
Seat heating in rear with automatic rear air conditioning
The seat heating switches are located in the FKA control panel.
The status of each seat heating switch is transmitted to the respective seat module (rear seat, driver's side and rear seat, passenger side) by means of a pulse-width modulated signal (PWM signal). If the energy management system requires a reduction in output, the heater output may be reduced in 3 stages or switched off completely.
Steering wheel heating (E70 only)
The steering wheel heating is integrated in the Steering Column Switch (SZL). The IHKA control unit transmits the signal for the steering wheel heating to be switched off (power-down command).
Electric steering column adjustment (E70 only)
The electric steering-column adjustment allows the driver to set the steering wheel to the best possible position. This is done with a switch on the left-hand side of the steering column. The tilt and the fore-and-aft setting of the steering column can be electrically adjusted.
Power for the electric steering column adjustment is provided via terminal 30g.
The IHKA control unit actuates the electric steering column adjustment.
When the steering column is adjusted, a Hall sensor on the steering column adjustment motor sends a signal the IHKA control unit. The position of the steering column is registered and stored by the IHKA control unit.
The position of the steering column can be stored for the Key Memory.
The tilt adjustment moves to the highest possible position to make it easier to get in and out of the vehicle.
For the easy-access facility, the steering-column adjustment is automatically activated under the following conditions:
- Terminal R OFF
- Terminal R ON and driver's door opened (signal via door contact)
- Terminal 15 OFF with driver's door open (signal via door contact)
The steering-column memory is activated under the following conditions:
- One of the two memory buttons is pressed (from terminal R ON).
- Another ID transmitter is used (personalisation).
Condition: The selection "Last seat position after unlocking" is activated in the "Settings" menu in the Central Information Display (CID).
In both cases, the steering-column memory will not move the steering column to the stored position until terminal 15 is switched ON.
Notes for service staff
Service staff should note the following points:
- General notes: [more ...]
- Diagnosis: ---
- Encoding/programming: [more ...]
National versions
Temperature display in °C (Celsius) or °F (Fahrenheit) can be selected with an on-board computer function.
Subject to change.