A/C System - Footwell Temperatures Too Hot
GROUP 64Heating and Air Conditioning
Bulletin Number
64 01 97
Woodcliff Lake, NJ
April 1997
Product Engineering
SUBJECT:
Footwell Temperature Excessive
MODEL:
E38
Complaint:
Footwell temperature is too hot when the customer has selected a temperature 68 F to 74 F and the outside temperature is between 50 F - 77 F.
Affected Vehicles:
All E 38 from start of production up to November 96 where the AC Control modules are equipped with blower speed control wheels. Versions of IHKA control modules which have rocker switches to control the blower speed are not affected.
Cause:
If the center dash outlet is set to max. cold position and the air vents are pointed downwards, the cold air flow is directed to the interior temperature sensor located in the IHKA control panel. This causes the IHKA interior air temperature sensor monitor a "cold" vehicle interior. The IHKA control module will try to compensate and to "heat up", particularly at the footwell outlets.
Correction:
In case of a customer complaint, recode the IHKA control module to alter the outside temperature compensation and minimize the heat increase in the footwell area using DIS.
This recoding can only be performed on control modules with software version 3.0 or 5.0 (software version 4.0 is not used in the US market).
Procedure:
In the diagnosis program of the DIS CDV 9.1 or higher select "Service functions", select "Alteration of outside-temperature influence with sporadic heating"
This modification can only performed once and DIS will display, "Alteration of the curve has already been performed" if any subsequent recoding steps are undertaken.
Warranty Status:
Labor and parts are reimbursable under the terms of the BMW New Car Limited Warranty.