IHKS System Components

IHKS System Components
The IHKS system consists of following components:
^ IHKS control panel/control module
^ IHKS heater/air conditioner unit
^ Refrigerant pressure sensor
^ Evaporator temperature sensor
^ A/C compressor
^ Rear window defogger relay





System Overview of INKS Input/Output Signals
The variations of the IHKS system as compared to the IHKA are described in the following pages.





IHKS Control Panel/Control Module





Plug connection, rear of IHKS Control Panel/Control Module

The rotary knob for air distribution (adjustment range of 360° rotation) features 3 rough settings and 9 fine settings.
The rotary knob for blower control (adjustment range of 104° rotation) provides the following setting options:
^ 1 rough setting for zero position
^ 8 fine settings for the 4 blower stages each with one intermediate stage
The rotary knob for temperature control (adjustment range of 244° rotation) provides the following setting options:
^ 23 fine settings over the complete adjustment range from cold to warm.

Note: The rotary function light and the vehicle interior temperature sensor are features of the IHKA only.

IHKS Heater/Air Conditioner
The following components are integrated in the IHKS heater/air conditioner unit:
^ Actuator, fresh air/recirculating air flap
^ Stepper motor, mixed air flap
^ Stepper motor, air distribution
^ Cam disc with microswitch
^ Blower output final stage and blower motor
^ Evaporator temperature sensor
The stepper motor for the air distribution and for adjusting the 3 air distribution flaps is mounted directly behind the cam disc. The Control module activates the stepper motor (corresponding to the required position) when the rotary control for air distribution is operated.





The cam disc moves the air distribution flaps by central kinematics. The actual position of the cam disc and stepper motor is detected by 2 small cams of different width that activate a microswitch.This microswitch provides feedback to the IHKS Control Module which corresponds to the air distribution flaps and their positions.
After KL15 is switched OFF and a sleep mode of 10 minutes, the flaps are moved to the following end positions:
^ Defrost flap dependent on outside temperature
> 10°C CLOSED (50°F),
< 10°C OPEN (50°F)
^ Ventilation flap CLOSED
^ Footwell flap CLOSED
A calibration run is carried out in the event of a system fault (e.g. implausible position of cam disc) to redetermine the position of the cam disc. The cam disc is moved until a cam trips the microswitch. Based on this position, a set position is specified and set in the control module.
A cam measurement (reference run) takes place the first time the control panel/control module is operated after:
^ Replacing the control panel/control module
^ Replacing the cam disc
^ Interruption in power supply
During this reference run, the length and distances of both cams with respect to each other are measured and stored in the control module. A fault code is stored if cam referencing cannot be concluded successfully after 3 attempts. In this case, adjustment of the central kinematics for air distribution is possible only within restricted limits.