Introduction

INTRODUCTION







The IHKA system is a fully automatic climate control system. The acronym IHKA is derived from the German words Integrierte Heizungs- and Klima-Anlage, which translates to "integrated heating and air conditioning system."

Interior heating and air conditioning (climate control) components and functions, separate on some earlier BMW systems, are integrated and work together to provide passenger comfort, regardless of ambient conditions. On IHKA systems, interior air discharge temperature is regulated by controlling the flow of hot engine coolant through the climate control system heater cores.

IHKA is classified as a fully automatic system because air distribution, air temperature and blower speed can be controlled automatically by the system control module.

IHKA systems also feature some "set and forget" automatic functions which serve to maintain interior comfort without any input from the vehicle occupants

IHKA first appeared in the U.S. on 1988 E32 (7-series) vehicles. E31 (8-series) vehicles, introduced three years later, use an IHKA system very similar to the E32 system.

An updated version of IHKA is installed on E38 (7-series) vehicles, beginning with the 1995 model year. The E36 (3-series), received IHKA in 1996, a system similar to the E38 system. The E39 (5-series) and E46 (3 series) have varied versions of IHKA

This course covers the following IHKA systems:

- IHKA E31: 1991 - 8/97
- IHKA E39: 1997 - present
- IHKA E38: 1995 - present
- IHKA E46: 1999 - present
- IHKA E36: 1996 - present


IHKA E38

The E38 IHKA system is a further development of the IHKA climate control system, but is very different from earlier IHKA systems in both construction and operation.

Important E38 differences (covered in detail later in this information) are listed below:

- The control module is integrated into the control panel.
- The blower speed control final stage unit is mounted on the blower motor assembly.
- The control panel/module has separate blower speed thumbwheels for the driver and passenger to regulate airflow separately on the left and right sides of the cabin.
- Face, footwell, and defroster vents can be opened individually or in combinations, using the separate "arrow" buttons on the control panel/module face.
- Left and right desired temperatures are changed using control panel rocker switches.
- Left and right desired temperatures appear in digital LED displays on the control panel face.
- Two additional temperature sensors are used, one at the left side and one at the right side of the center face vent outlet.
- Stratified air is available from the console rear outlet, and controlled by a thumbwheel at that outlet.
- Flap stepper motors are "smart"motors; each contains a microprocessor.
- The microfilter assemblies are integrated into the vehicle hood.
- The recirculating air function can be activated using a button on the steering wheel.
- A new function, automatic recirculating air (AUC), is activated automatically when poor ambient air quality is sensed.
- The control panel/module face includes a "REST" button for this new function, which uses the IHKA system to heat the passenger compartment for a short period after the ignition is switched "Off."
- The windshield base heater present on early E32 vehicles is again available.