Test Description

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The numbers below refer to the step numbers on the diagnostic table.

8. This step verifies that the auxiliary HVAC control module is commanding the auxiliary blower motor to operate at HI speed to reflect the requested speed of the front auxiliary HVAC control assembly. The scan tool should display a value greater than 50 percent.
11. This step tests for an internal fault of the RSA control module, or the auxiliary HVAC control module. If the Rear HVAC Fan Speed parameter changes as the fan switch speed changes then replace the auxiliary HVAC control module. If the Rear HVAC Fan Speed parameter does not change replace the RSA control module.
12. This step verifies that the front auxiliary HVAC control assembly receives a 5 V reference and ground from the auxiliary HVAC control module. If all 3 parameters are at 0 when the auxiliary fan HIGH speed is requested then proceed to step 13.
15. This step verifies that the auxiliary HVAC control module is commanding the auxiliary blower motor to operate at HI speed to reflect the requested speed of the front auxiliary HVAC control assembly. If the Blower Switch Pos. parameter is 15 and the auxiliary blower motor is not on HIGH then replace the auxiliary HVAC control module.

Fig 1: Diagnosis Procedure Blower Motor Inoperative - Auxiliary (Step 1 To 6)
Courtesy of GENERAL MOTORS CORP.

Fig 2: Diagnosis Procedure Blower Motor Inoperative - Auxiliary (Step 7 To 15)
Courtesy of GENERAL MOTORS CORP.

Fig 3: Diagnosis Procedure Blower Motor Inoperative - Auxiliary (Step 16 To 25)
Courtesy of GENERAL MOTORS CORP.

Fig 4: Diagnosis Procedure Blower Motor Inoperative - Auxiliary (Step 26 To 32)
Courtesy of GENERAL MOTORS CORP.