A/C System - Description

90bmw12 Group 64 Heating and Air Conditioning
Bulletin Number 64 01 90 (2101)
Woodcliff Lake, NJ July 1990 Service Engineering
SUBJECT: IHKR 2

MODEL: E34



General
Information: From week 2 of 1990, a revised A/C system has been phased into E34 production, replacing the IHKR 1 system used so far. The new system is designated IHKR 2 (integrierte Heizungs - und Klimaregelung 2 Generation).
The IHKR 2 system can be easily indentified by the new push buttons for air conditioning, recirculation/AUC (Automatic Circulation Control) and rear window defrosting. The push buttons now have LED's to indicate engagement. (The AUC function is in preparation).


The IHKR 2 system incorporates the following features:

1) The lower part of the housing has a simpler water drain for condensation, and a newly designed heater core.
2) There are only three stepper motors for fresh air, recirculated air, and stratified air regulation; the air outlets for front and rear footwell areas are cable operated.
3) Heater blower control is by selection of fixed resistors rather than by manipulation of blower final stage transistors.
4) The control unit has three 26-pin connectors, and is mounted at the front of the heater housing (similar to that IHKR 1).
System

Diagnosis: IHKR 2 can be diagnosed with version 8.0 (and later) software.

Parts

Information: IHKR 2 control units are available coded or uncoded.

Coding: Uncoded control units must be coded before installation. The variants are:


- leftor right-hand drive

- with or without AUC (Automatic Circulation Control).


Coding of the control unit is possible with version 8.0 (and later) software and can be performed an indefinite number of times.

Microfilter: The IHKR 2 system can not be fitted with a microparticle filter.