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For 1990-2009 cars only

Poor AC Performance - keywords compressor core evaporator HVAC performance sensor temperature

Subject:Poor AC Performance

Models:2004-2005 Chevrolet Colorado Pick Up
2003-2006 Chevrolet SSR
2004-2005 GMC Canyon Pick Up



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

Condition/Concern:

Poor AC performance.

Recommendation/Instructions:

After following published diagnostics and no faults have been found, follow the recommend repair procedure below.

  1. Inspect the evaporator temperature sensor module color. This module can be located on the passenger's side of the HVAC case, near the glovebox opening.
  2. If the module is Blue in color, replace the evaporator temperature sensor/module assembly with part number 89018791.
  3. If the evaporator temperature sensor module is Green in color, this is the updated part. If this new part is suspected to be a concern, order part number, 89018791. Remove the module from the HVAC case leaving the sensor inside the HVAC case and only replace the module. This can be done by using a splice connection.

Caution: Do not mix the blue module and green module or the temperature probes. These probes are manufactured by 2 different vendors and are not interchangeable. If a green module is installed, splice with parts from a new green module ONLY. If a blue module is installed, replace the entire part with a green module part number 89018791.

Note: The Evaporator Temperature Sensor/Module assembly part number 89018791 consists of a sensor that clips to the evaporator core and a logic module.

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.