GM Service Manual Online
For 1990-2009 cars only

Various HVAC Concerns And DTCs - keywords B0229 B0263 B0268 B0408 B0414 B0418 B0424 B3770 blow blower cold hot mode temperature warm

Subject:Various HVAC Concerns And DTCs

Models:2003-2006 Cadillac Escalade, Escalade ESV, Escalade EXT
2003-2006 Chevrolet Avalanche, Suburban, Tahoe
2003-2007 Chevrolet Silverado Classic
2003-2007 GMC Sierra Classic
2003-2006 GMC Yukon and Yukon Denali Models
2003-2007 Hummer H2



This PI is being updated to specify location. Please discard PIT3504C.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some customers may comment on various HVAC concerns including temperature doors defaulting to full hot position or unable to obtain defrost position. Upon inspection, technicians may find DTCs B0414, B0424, B3770, B0418, B0408, B0263, B0268, and/or B0229 are set.

Recommendation/Instructions:

Check the Right I/P junction block connectors C4, C5, and C8 (Document ID # 1562972) for poor terminal tension, backed out terminals or connectors not fully seated.

Please follow this diagnostic or repair 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.