21
2001 model year changes
IHKA integrated heater and air conditioning case
The E39 IHKA case has been redesigned since 3/00. The E39 and E53 both share the
same case design.
The difference from the previous case is that a single flap (left and right), controls both the
fresh air and recirculation inlets. Ram air is controlled by a separate flap. What makes it
possible to use a single flap for fresh air/re-circ is the semi-circular door; as one inlet is cov-
ered another is opened.
Please refer to the Climate Control course material ST 054 for a complete functional description of
ram air pressure compensation.
1. Stepper motor for footwell
2. Stepper motor for rear compartment, stratification
3. Fresh air/recirculation flap
4. Output stage for blower motor
5. Stepper motor for ram air flap
6. Ram air flap
Stepper motors for the fresh air/recirculation,
defrost and ventilation flaps are located on the
left side of the housing
3
6
4
2
1
5
Right Side of IHKA IV Case
Ram air and fresh air/re-circ flaps as seen from the engine side of the bulkhead
