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Heater Duct - Condensation Dripping

Group Ref.: 1 - HVAC

Bulletin No.: 431106

Date: August, 1994

SUBJECT:
CONDENSATION DRIPPING FROM HEATER DUCT (INSTALL WATERTIGHT DAM IN HVAC CASE)

MODELS:
1992-94 CADILLAC ELDORADO AND SEVILLE
1994 CADILLAC CONCOURS AND DE VILLE

CONDITION:

Some owners 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:

Water that normally drains out of the HVAC case is picked up by the high speed air and carried into the joint area 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.

CAUTION:
This vehicle is equipped with the Supplemental Inflatable Restraint (SIR) system. Refer to the cautions in Section 9J under "On-vehicle Service" in the appropriate Service Manual 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. Using the proper procedures listed in Section 1B of the appropriate Service Manual, remove the air distribution duct assembly to gain access to the HVAC case/air duct joint area. Refer to Figure 1.

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 with 3M brand # 08984 general purpose cleaner, or equivalent, to remove any traces of contamination that may prevent a good bond between the pieces.

4. Apply adhesive 3M brand # 88641, or equivalent, to the mounting surfaces of the dam and the HVAC case. Place the dam in the illustrated position. Refer to Figure 1. 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.

IMPORTANT:
In order for this 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. Remove tape and reassemble the HVAC and dash assembly using the procedures found in the appropriate Service Manuals.

PARTS INFORMATION:

Parts are currently available from GMSPO.





WARRANTY INFORMATION:
For vehicles repaired under warranty, use: (see illustration)