A/C - Poor Heat Output With Grille Cover Installed
TECHNICALBulletin No.: 11-01-39-005A
Date: February 01, 2013
Subject: Reduced Heater Performance with Winter Grille Cover Installed
Models:
2007-2013 Chevrolet Silverado 2500/3500 Series
2007-2013 GMC Sierra 2500/3500 Series
Equipped with Duramax(TM) Diesel Engine (RPO LMM, LML or LGH) Combined with RPOs CJ2 and V10
Supercede:
This bulletin is being revised to add the 2013 model year. Please discard Corporate Bulletin Number 11-01-39-005 (Section 01 - HVAC).
Condition
Some customers may comment on reduced heater performance or the need to increase the climate control temperature settings when using the winter grille cover (Cover, 1-piece, covers radiator grille for diesel engines in winter weather).
Cause
The winter grille cover restricts airflow, allowing the underhood temperatures to increase. This provides an elevated temperature signal to the HVAC system. This may cause the automatic temperature control to reduce the amount of heat being delivered to the passenger compartment.
Correction #1 for Model Year 2011-2013 Vehicles
Relocating the ambient air temperature sensor will allow the sensor to continue detecting cooler air.
Use the following steps to relocate the ambient air temperature sensor into the lower bumper opening using a remote mounting bracket.
1. Remove the radiator air upper baffle/deflector. Refer to Radiator Air Upper Baffle and Deflector Replacement in SI.
2. Carefully remove the ambient air sensor from the radiator support.
3. Remove the wire retainer closest to the sensor.
4. Relocate the sensor and sensor harness in front of the transmission oil cooler as shown.
5. Locate the right vertical support section of the core support lower cross member.
6. Mark the center of the vertical support with a paint pen as shown and center punch the mark at the drill location.
7. Drill a 3 mm (1/8 in) hole. Use care to not damage the transmission oil cooler or the radiator.
8. Coat the hole with GM Synthetic Lubricant With Teflon(R), P/N 12371287 (in Canada, use 10953437), to prevent corrosion.
9. Using a large flange, 1/8 in. shank rivet, such as *Kent Industries part #P57356 or the equivalent, rivet the service bracket to the cross member as shown.
10. Install the temperature sensor into the bracket as shown.
- If the retention fins on the sensor mounting pin were damaged when removing the sensor, the sensor may be loose in the bracket.
- If the sensor is loose in the bracket, install a push tight retainer such as *Kent Industries part #P42999 or the equivalent as shown.
11. Reinstall the radiator air upper baffle/deflector. Refer to Radiator Air Upper Baffle and Deflector Replacement in SI.
*We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources.
Correction #2 for Model Year 2007-2010 Vehicles
For vehicles equipped with Automatic Temperature Control HVAC (RPO CJ2), the ambient (outside) air temperature sensor needs to be relocated.
Use the following steps to relocate the ambient (outside) air temperature sensor.
1. Remove the radiator grille. Refer to the Radiator Grille Replacement procedure in SI.
2. Remove the ambient air sensor from its current location by carefully lifting the sensor from the radiator support cross bar.
3. Remove the harness clip nearest to the sensor.
4. Reinstall the ambient air sensor to the new location using the existing hole (1) in the lower section of the radiator support.
5. Reinstall the harness clip to the existing hole (2) in the radiator support.
6. Reinstall the radiator grille. Refer to the Radiator Grille Replacement procedure in SI.
Parts Information
*Contact Kent Automotive at 1-888-YES-KENT or online at www.kent-automotive.com.
Warranty Information
For vehicles repaired under warranty, use the table.
Disclaimer