16
2001 model year changes
The IHKR control module communicates with the DME via the K-Bus/KOMBI/CAN Bus
link to request permission for compressor activation. The control of the compressor
clutch is directly by the IHKA module via a final stage.
Rear Window Defroster:The rear window defroster is controlled via a request from
the button on the panel. After switching on for the first time, the rear window is heated
for 10 minutes. Output voltage to the window is provided by the K13 rear defogger
relay. After automatic switch off, if the button is pressed once again the control unit will
pro vide a clocked operation alternating at 40 seconds on and 80 seconds off. If the
vehicle voltage drops below 11.4V during this second heating operation the function is
stopped, however the LED on the button will not be extinguished. If voltage increases
past 12.2V for at least one second, clocked operation will resume. Clocked operation
continues until the button is pressed again or the ignition is cycled.
Washer Jet Heating:The IHKR provides operating current to the washer jet heaters
based on outside temperature. The washer jets are heated below an outside
temperature of 37
oF.
K-Bus Communication:The IHKR control unit is on the vehicle K-bus and receives
and sends information concerning:
Engine temperature, RPM, KL61, KL50, compressor request, auxiliary fan request,
compressor load (DME)
Outside temperature KL15 and road speed (KOMBI)
Diagnosis and coding (DIS/MoDiC)
Ventilation Flap
Stratification flap
Heater Core
Defrost Flap
Evaporator
Outlet, rear footwellOutlet, Rear compartment
Blower
Left side of IHKR case
17
2001 model year changes
IHKA IV
The IHKA system is standard equipment on 530i, 540i/it and M5 models. It is available as
an option for the 525i/it. IHKA has been redesigned for the 2001 E39, it is identified as
IHKA IV. The carry over features from the previous version are:
Integrated control panel/module.
Separate temperature control for driver and passenger.
Air distribution control through the use of 5 “smart” stepper motors and one fast acting
hard wired stepper motor.
Automatic recirculation control (AUC).
Recirculation control via MFL.
“Rest” function for residual heat when engine is not running.
Service station feature that closes the water valves when stopped to prevent hot coolant
flooding the heater core.
A/C compressor clutch activation via a final stage control.
Stratification flap control via a bowden cable.
Please refer to the Climate Control course material ST 054 for a complete functional description of
E39 IHKA
70 0 F 640 F
-+AUTO
A
AUTO
MAX
