3656
Service Bulletin Details
Public Details for: 3656
Repeat rear blower motor failure or inoperative. *tt updated 12/5/08. *pe updated 08/06/2012 *js
- 2006 - 2005 - 2004 - 2003 - 2002 -
Models from 2006
| 2006 CHEVROLET TRAILBLAZER EXT |
| 2006 GMC ENVOY XL |
Models from 2005
| 2005 CHEVROLET TRAILBLAZER |
| 2005 GMC ENVOY |
Models from 2004
| 2004 CHEVROLET TRAILBLAZER |
| 2004 GMC ENVOY |
Models from 2003
| 2003 CHEVROLET TRAILBLAZER |
| 2003 GMC ENVOY |
Models from 2002
| 2002 CHEVROLET TRAILBLAZER |
| 2002 GMC ENVOY |
SB-10017014-9267 File in Section: Service Bulletin - Bulletin No.: PIT3656B Date: July, 2012 PRELIMINARY INFORMATION Subject: Repeat Rear Blower Motor Failure or Inoperative Models: 2002 - 2006 Chevrolet Trailblazer EXT 2002 - 2006 GMC Envoy XL This PI was superseded to update recommended field. Please discard PIT3656A. The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI. Condition/Concern: After replacing the rear HVAC blower motor processor (resistor), repeat failures have occurred. Some Service information refers to a thermal gasket that mounts between the blower motor processor (resistor) and the HVAC case. This thermal gasket is now incorporated in to the new blower motor processor (resistor). The blower motor resistor uses the evaporator core as the heat sink. If the new blower motor processor (resistor), is not making good contact with the evaporator the resistor temperature will raise until a thermal limit inside the module is reached. Then the resistor will default to an inoperative state. When the resistor lowers below its thermal state, the rear blower motor begins to operate again. Recommendation/Instructions: When installing the blower motor processor, the HVAC case needs to be removed so the blower motor processor is installed correctly in to the case and making good contact with the evaporator core. Make sure the blower motor processor is making good contact with the evaporator core. It will be necessary to apply thermal grease to the blower motor processor. Please obtain Dow Corning 340 Heat Sink Compound from a local distributor. Another concern may occur when the screw(s) that retain the blower motor resistor are lost and a longer screw(s) are used as a replacement. If the screws are too long, the module will not apply enough pressure against the evaporator to make contact to dissipate the heat generated from the resistor. If either of the retaining screws is lost, replace them with the exact length and diameter that was removed. If both screws are lost, it will be necessary to obtain the size and diameter screw from a like vehicle. 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. SB-10017014-9392 File In Section: Bulletin No.: Date: Service Bulletin PIT3656A September, 2008 PRELIMINARY INFORMATION Subject: Repeat Rear Blower Motor Failure or Inoperative Models: 2002-2006 Chevrolet Trailblazer EXT 2002-2006 GMC Envoy XL This PI was superseded to update model years. Please discard PIT3656. The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI. Condition/Concern: After replacing the rear HVAC blower motor processor (resistor), repeat failures have occurred. This concern may be caused by one of the following two items: 1. It has been noted when replacing this module, the ″thermal gasket″ that rests between the blower motor resistor and the HVAC case may fall off the HVAC case or the resistor. This thermal gasket is a thin square piece of aluminum (foil type) that mounts between the resistor and the HVAC case. With this gasket missing, the resistor temperature will raise until a thermal limit inside the module is reached. Then the resistor will default to an inoperative state. When the resistor lowers below its thermal state, the rear blower motor begins to operate again. 2. A second concern may occur when the screw(s) that retain the blower motor resistor are lost and a longer screw(s) are used as a replacement. If the screws are too long, the module will not apply enough pressure against the thermal gasket or make contact and the thermal gasket cannot dissipate the heat generated from the resistor. Recommendation/Instructions: To avoid this concern, follow eSI Document ID # 748863 completely. 1. Make sure that when removing the blower motor resistor from the HVAC case, the ″thermal gasket″ does not drop behind the HVAC case. When installing the blower motor processor, make sure the thermal gasket is installed between the blower processor module and the HVAC case. It will be necessary to apply the supplied grease to the Copyright 2008 General Motors Corporation. All Rights Reserved. gasket. The ″thermal gasket″ must be free of any dirt. If the thermal gasket is missing and cannot be found in the vehicle, a new blower motor resistor can be ordered and the new thermal gasket is packaged with the blower motor resistor. 2. If either of the retaining screws are lost, replace them with the exact length and diameter that was removed. If both screws are lost, it will be necessary to obtain the size and diameter screw from a like vehicle. 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.