A/C - Moisture Condensation on Interior Windows

Group Ref.: HVAC

Bulletin No.: 431206

Date: March, 1994

SUBJECT:
MOISTURE CONDENSATION ON INTERIOR WINDOWS (REMOVE SECTION OF DASH INSULATOR MAT)

MODELS:
1994 BUICK REGAL
1994 CHEVROLET LUMINA
1994 OLDSMOBILE CUTLASS SUPREME
1994 PONTIAC GRAND PRIX
FOR VEHICLES BUILT BEFORE NOVEMBER 1, 1993

CONDITION:

Customer may comment about tendency for moisture to condense on interior windows.

CAUSE:





The dash insulator mat can interfere with the air inlet valve (sometimes referred to as the A/C "recirc" door). This can cause the valve to be stuck in the max (recirc) position causing inside air to be recirculated. See Figure 1.

DIAGNOSIS:

A good indication of this condition can be verified by putting blower in high speed and changing modes from normal A/C to max A/C. If no change in loudness occurs (or if the sound change is very subtle) the valve could be hanging up in the max (recirc) mode. However, it is possible for the valve to be partially open. Any vehicle built prior to November 1, 1993, exhibiting this condition, should be visually inspected.

NOTE:
Although the condition may be accompanied by condensation on windows, it does not have a significant affect on windshield defrost performance.

CORRECTION:

OLDSMOBILE ONLY

1. Lift out glove box.

2. Verify that door is stuck in the open (max A/C) position.

3. Remove right side sound insulator (hush panel). Refer to the Service Manual Section SC for procedure.

4. Remove convenience center. Refer to the Service Manual Section 80 for procedure.

5. Remove vacuum electric solenoid harness.





6. Remove a section of insulator mat, approximately 3" X 6" (75 mm x 150 mm), above air inlet valve with a utility knife. See Figure 2.

7. Cycle through max and normal A/C modes to be certain that door will not hang up on dash insulator mat.

8. Install vacuum/electrical solenoid harness.

9. Install convenience center.

10. Install right side sound insulator.

NOTE:
To check for proper operation of vehicles with Automatic Control Air Conditioning (C68) systems it is necessary to do the following:

Set temperature to "60" and select "AUTO" setting. Wait for one full minute for door to open. Toggle between "60" and "65" to check that door is not hanging up on Insulator mat.

BUICK, CHEVROLET AND PONTIAC

1. Remove glove box and right side sound insulator (hush panel). Refer to Service Manual Section 8C for procedure.

2. Verify that door is stuck in the open (max A/C) position.

3. Remove right side window defog tube.

4. Remove a section of insulator mat, approximately 3" X 6" (75 mm X 150 mm), above air inlet valve with a utility knife. See Figure 2.

5. Cycle through max and normal A/C modes to be certain that door will not hang up on dash insulator mat.

6. install right side window defog tube.

7. Install glove box and right side sound Insulator (hush panel).

WARRANTY INFORMATION:

For vehicles repaired under warranty, use:

Labor Operation: T-3454

Labor Time: 0.5 Hr. Buick

0.4 Hr. Chevrolet

0.4 Hr. Oldsmobile

0.3 Hr. Pontiac