Water Leak from HVAC Case - carpet condensation wet

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Water leaking or wet carpet below the HVAC case on the passengers side.

Vehicles built after 5/28/02, VIN 30115764 have been corrected at the plant.

Perform the following steps.

1. Remove passenger door sill trim.
2. Peel back the passenger side carpet up to the passenger seat, keeping seat in car.
3. Detach rear passenger foot duct from heater and A/C module (HVAC) using flat screwdriver to unsnap lock tabs, or just twist and pull the duct.
4. Detach wire harness from rear duct at multiple points.
5. Pull rear heat duct forward and remove from vehicle.
6. To dry out HVAC module, place control panel in foot mode, a/c off, max hot, high blower, and run for about ten minutes.
7. Turn off the climate control panel
8. Wipe off bottom of HVAC module to dry off.
9. From driver’s side, wedge the handle end of a skinny screwdriver between the plastic drain end and rubber tunnel insulator mat, to hold down the insulator mat.
10. For surface preparation of the two HVAC case seams, sand the plastic seams and follow directions on sealer tube for cleaning procedure which includes using paint thinner so as to remove any release agents or surface contamination for good RTV adhesion.
11. Using a tongue depressor type of wooden stick, or a paint stirrer, apply ample silicone sealer 3M Part Number 08662 or GM part number 12346192 (squeeze tube) or 12346286 (caulk gun). About a 1/4" to 1/2" bead along entire bottom of HVAC case seam, creating a continuous seal from the front side to the rear side of the case. Any missed portion will become a new leak point.
12. After getting the silicone on the case, use your fingers to dab the silicone upwards tight to the case.
13. Using only your fingers, continue the silicone 1" up the rear of HVAC case to the first screw boss.
14. Continue the silicone 1"-2" up the front of the case.
15. Pay special attention applying silicone to the bottom front of the case passenger side where the seam is lower on the driver side than it is on the passenger side.
16. Allow silicone one hour to dry.
17. Run vehicle with a/c on for a half hour to check for water under the case.
18. Put the car back together, making certain that the right rear foot duct is fitted into the duct outlet trim piece under the passenger seat.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

03 Cadillac CTS