IHKA Compared With IHKR

IHKA COMPARED WITH IHKR

IHKA E32 and E31 systems are very similar in design and function to the IHKR E34 systems covered in the IHKR Handout:

- The IHKA control panel has:
- on/off push-buttons to operate the A/C compressor; rear window defroster (except E31), and recirculating air function.
- thumbwheels to select driver-side (left) and passenger-side (right) desired
- temperatures.
- blower-speed thumbwheel to select blower speed.

- Heater core divided into two sections (left and right sides).
- Auxiliary pump to maintain coolant flow through the heater cores.
- Five NTC-thermistor type temperature sensors.
- Motor-driven fan mounted on back of control panel to pull air over over the interior temperature sensor.
- Blower assembly having a single motor with twin squirrel-cage impellers.
- Blower speed electronically controlled by a final stage unit.
- Electric stepper motors 10 operate the air intake, air distribution, and temperature mixing flaps.
- Solid state electronic system control module that can recognize component/circuit faults, store specific codes in memory, and operate using a "substitute value" for the faulty component/circuit.
- Control thumbwheel at the center face-vent outlet to provide stratified air.

The most significant difference between the IHKA E32/E31 systems and the IHKR systems is that in IHKA systems, air distribution flaps and blower speed can be controlled automatically by the control module.

IHKA E38 and E36, while based on the earlier IHKA systems, have more significant differences.