AC problem: any tsb?

400hp · May 16, 2005

2001 GMC sierra. AC stopped blowing cold. It was intermittent for a while and when it was i found a problem with the blend door. If it was blowing cold and i turned the heat select over to hot and then back to cold, it wouldnt come back to cold. It would stay blowing hot. Is there any TSBs on AC box blend doors or any known prob;ems with these? the doors are electrically opened right? is there a flow chart i can follow on this? I am going to check ac pressures at work today to make sure i have refridgerant.

thx for any help,

mike

GM-Tech · May 16, 2005

Dunno if this is your problem...

Loss of HVAC System Mode and/or Temperature Control (Reroute Wiring Harness) #01-01-39-007 - (Dec 20, 2001)

1999-2002 Chevrolet and GMC C/K Pickup Models (Silverado and Sierra)

1999-2002 Chevrolet and GMC C/K Utility Models (Avalanche, Surburban, Tahoe, Yukon, Yukon XL, Denali)

2001 GMC Sierra C3

2002 GMC Sierra Denali

2002 Cadillac Escalade, Escalade EXT

Condition

Some customers may comment that they cannot control the HVAC system modes and/or the temperature. These concerns may be intermittent.

Cause

There may be poor terminal contact and/or bent terminals in connectors C206 (RPO C68 automatic HVAC controls) or C296 (RPO C60 manual HVAC controls). Excessive tension on the wires due to the wiring harness being misrouted in the instrument panel carrier may cause these conditions.

Correction

Remove the Air Bag fuse.

Disconnect the steering wheel and instrument panel (IP) air bag connectors. Refer to the SIR subsection of the Restraints section of the Service Manual for connector locations.

Remove the IP upper trim pad.

Locate connector C206 (6 cavities) or C296 (8 cavities). The connector is attached to a metal brace on the far right side of the IP carrier above the IP air distributor duct.

Inspect the routing of the wiring harness to the connector. The proper routing of the wiring harness is above the air distributor duct with no tension on the terminals in the connector. The routing is improper if the wiring harness is below the air distributor duct with excessive tension on the terminals in the connector. The excessive tension may cause poor terminal contact, resulting in open circuits, in the connector. The wires may also pull the terminals out of the connector or pull out of the terminal itself.

If the harness is routed properly, contact Technical Assistance for further information.

If the harness is misrouted, remove the connector from the brace.

Disconnect the connector.

Perform a pin drag test on the female terminals.

Inspect the male terminals for straightness.

Inspect the wire to terminal connection to insure that no wires have pulled out of the terminals.

Reroute the wiring harness above the air distributor duct.

Firmly reconnect and reseat the connector.

Reattach the connector to the metal brace.

Reinstall the IP upper trim pad.

Turn Off the ignition and reconnect the steering wheel and IP air bags.

Reinstall the Air Bag fuse.

Turn ON the ignition and verify that the air bag light flashes seven times and goes out.

Clear any diagnostic trouble codes that may have been set.

Verify proper operation of the HVAC system mode and temperature controls.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

C2362

Panel, Instrument Panel Upper, Remove and Replace

0.7 hr

Add

To Repair and/or Reposition Connector and Harness

0.3 hr

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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