Heater Duct - Condensation Dripping Into Interior

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NUMBER: 91-T-143

CORP.REF.NO: 101101

DATE: June 1991

SECTION: 1B, 8C


SUBJECT:
CONDENSATION DRIPPING FROM HEATER DUCT INSTALL WATERTIGHT DAM


MODELS/YEARS:
1991 NINETY-EIGHT


CONDITION: Some 1991 Ninety-Eight vehicles in high ambient, high humidity areas may experience a condition where condensation drips from the HVAC air distribution duct when the blower is on high speed.

CAUSE: High speed air picks up water in the temperature door area that normally drains out of the HVAC case blowing it past the joint between the Air Distribution duct and the HVAC module where it then leaks out onto the floor.





CORRECTION: Install a watertight dam (P/N 52460676) on the floor of the HVAC case overlapping the air distribution duct joint. Part Number 52460676 is currently available from GMSPO.

Caution: This vehicle is equipped with the Supplemental Inflatable Restraint (SIR) System. Refer to cautions in Section 9J under on-vehicle service before performing service on or around SIR components or wiring. Failure to follow cautions could result in possible air bag deployment, personal injury or unneeded SIR system repairs.

Caution: Before removing or installing any electrical components, disconnect the negative battery cable to help prevent personal injury and/or damage to the vehicle or its components.

Procedure:
1. Follow Section 8C/1B to remove the air distribution duct assembly from the dash. See the illustration on the back of this bulletin.
2. Scuff the mounting surface of the dam and the HVAC case with 220 grit sandpaper. This is the outside lip of the module case that fits inside the modular duct. Be sure both surfaces are clean and dry when finished.
3. Wipe the case and the dam clean with 3M(R) No. 08984, general purpose cleaner or equivalent, to remove any traces of contamination that may prevent a good bond between the pieces.
4. Apply 3M(R) No. 08641 adhesive or equivalent to the mounting surfaces of the dam and the HVAC case. Place the dam in the illustrated position. Make sure that the mounting tab is facing the heater core.
5. Temporarily tape the dam in position for 30 minutes to allow the sealer to set. In order for this repair to be effective, it is important that the dam be completely watertight. If necessary, run a second bead of sealer around the adjoining surfaces.
6. Reassemble the HVAC and dash assembly as per the service manual.

WARRANTY INFORMATION:
Labor Operation No.: T5220
Labor Time: 2.7 hour.
Add: 0.7 hour for console
Trouble Code: 92