HVAC System - May Intermittently Turn On

FILE IN SECTION: 1 - HVAC

BULLETIN NO.: 43-11-08

DATE: November, 1994

SUBJECT:
HVAC System May Intermittently Turn On in Defog or Defrost Mode by Default (Splice Wire into Circuit)

MODELS:
1992-94 Buick LeSabre, Park Avenue

CONDITION

Some owners may comment that the HVAC system turns on in "Defog" or "Defrost" mode when the vehicle is first started but was not in that mode when it was shut off. For example, the system may have been in "Normal" mode when the vehicle was turned off and the system is in "Defrost" mode when the vehicle is turned on. This condition is more noticeable when the blower fan is left in medium 1 or medium 2 positions.

CAUSE

The HVAC blower fan is feeding voltage back to the HVAC control during power down. The HVAC control thinks it is a button press and changes mode.

CORRECTION

Note:
* = 1992-93 models
** = 1994 models

1. Remove blower speed relay from underhood fuse block.




2. Remove terminal *1/**3O and wire (circuit *5O/**41) from underhood fuse block (see illustration).

3. Cut terminal off wire and tape back harness.

4. Strip circuit *1444/**442 in an area to allow for splicing.

5. Splice a wire into circuit *1444/**442 using splice clip, P/N 1839906, which can be found in terminal repair kit (J 38125). Follow the procedure for splicing copper wire using splice clips in the Service Manual.

6. Attach terminal to other end of wire and insert into underhood fuse block terminal *1/**3O.

7. Reinstall blower speed relay in underhood fuse block.

PARTS INFORMATION

Parts are currently available from GMSPO.

WARRANTY INFORMATION

For vehicles repaired under warranty. use:

Labor Operation Labor Time
N6030 Use published labor operation time.