General

Operation
The automatic climate control system (IHKR) is a water-based automatic heating and air conditioning system. The control system on the water side is based on two electrically operated water valves in separate heat exchangers on the left and right sides.

The required temperature in the vehicle is controlled by a mixing flap. The air is mixed ahead of the heat exchangers without being heated in the flow of ventilation air. Temperature control with mixing flaps is therefore not possible when the ventilation outlet grilles are closed manually.

The control unit performs open-loop and closed-loop control functions with the aid of a microcomputer:
- Control of recirculated air and footwell flaps
- Temperature mixing control
- Air flow control
- Interior temperature control
- Rear window defogger control
- Evaporator temperature control
- Auxiliary water pump control
- Defect detection and diagnosis and making available a substitute value for failed components





Control Panel

IHKR1 (Automatic Climate Control System) Up to Jan. 1990:

General Block Diagram