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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1418 (HVAC Systems - Automatic) >> Diagnostic Information and Procedures >> Blower Motor Inoperative - Auxiliary (VIN 3 including Envoy XUV) >> Test Description

Test Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
  1. 2:  The auxiliary system will not operate with the primary system in the DEFROST position.
Blower Motor Inoperative - Auxiliary (VIN 3 including Envoy XUV)

Step Action Yes No
Schematic Reference: HVAC Schematics 
Connector End View Reference: HVAC Connector End Views 
DEFINITION: The auxiliary blower motor is inoperative in all blower motor switch positions.
1 Did you perform the HVAC Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - HVAC Systems - Automatic 
2
IMPORTANT: The auxiliary blower motor only operates at MEDIUM and HIGH speed. When the auxiliary blower switch is placed in the lowest speed setting the air flow through the center console to the rear is provided by the primary blower motor. The air speed will vary depending on the front blower motor setting.
  1. Turn ON the ignition, with the engine OFF.
  2. Place the primary mode switch on the HVAC control module to the floor position.
  3. Place the front blower motor switch in the minimum speed position.
  4. Place the auxiliary blower motor switch in the medium speed position and the maximum speed position.
Does the auxiliary blower motor operate in either of the speed positions?		 Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3
  1. Cycle the auxiliary blower switch through all speed positions:
  2. Observe the Rear HVAC Fan Speed parameter in the Rear HVAC/RSA data list.
Does the Rear HVAC Fan Speed parameter change with each command?		 Go to Step 4  Go to Step 7 
4
  1. Turn OFF the ignition.
  2. Disconnect the auxiliary blower motor.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the auxiliary blower motor high speed control circuit and a good ground.
  5. Place the auxiliary blower motor switch in the maximum speed position.
Does the test lamp illuminate?		 Go to Step 5  Go to Step 7 
5 Test the ground circuit of the auxiliary blower motor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 10  Go to Step 6 
6 Inspect for poor connections at the harness connector of the auxiliary blower motor. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 10  Go to Step 8 
7 Inspect for poor connections at the harness connector of the auxiliary HVAC control module. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 10  Go to Step 9 
8 Replace the auxiliary blower motor. Refer to Blower Motor Replacement - Auxiliary (Rear Auxiliary) or Blower Motor Replacement - Auxiliary (Front Auxiliary) in Heating, Ventilation and Air Conditioning.
Did you complete the replacement?		 Go to Step 10  -
9 Replace the auxiliary HVAC control module. Refer to HVAC Control Module Replacement - Auxiliary .
Did you complete the replacement?		 Go to Step 10  -
10 Operate the system in order to verify the repair.
Did you correct the condition?		 System OK Go to Step 3 
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