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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1712 (HVAC Systems - Automatic) >> Diagnostic Information and Procedures >> DTC B0429 >> Test Description

Test Description

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

  1. 3:  This step determines if the auxiliary air temperature door position is within the specified range of the commanded value.
  2. 6:  Tests for a short to voltage in the 5 volt reference circuit.
DTC B0429

Step Action Values Yes No
Schematic Reference: HVAC Schematics 
1 Did you perform the HVAC Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - HVAC Systems - Automatic 
2
  1. Install the scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, check the DTC.
Does the scan tool indicate that DTC B0248, B0268, B0408 and B03531 set along with B0429?		 - Go to Diagnostic Trouble Code (DTC) List  Go to Step 3 
3 
  1. Install the scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, observe the Aux. Mix Door Commanded data parameter and the Aux. Mix Door Actual data parameter in the Auxiliary ECC Data list.
Does the scan tool indicate that the Aux. Mix Door Commanded data parameter is within the specified value of the Aux. Mix Door Actual data parameter?		 0-3 Counts Go to Diagnostic Aids Go to Step 4 
4
  1. With the scan tool, command the air temperature actuator from HOT to COLD.
  2. With the scan tool, observe the Aux. Mix Door Actual parameter.
Does the Aux. Mix Door Actual data parameter change at all?		 - Go to Step 9  Go to Step 5 
5 Test the ignition 3 voltage circuit of the auxiliary air temperature actuator for an open or a high resistance. Refer to CIRCUIT TESTING and WIRING REPAIRS .
Did you find and correct the condition?		 - Go to Step 15  Go to Step 6 
6  Test the 5 volt reference circuit of the auxiliary air temperature actuator for an open, high resistance, short to ground or short to voltage. Refer to CIRCUIT TESTING and WIRING REPAIRS .
Did you find and correct the condition?		 - Go to Step 15  Go to Step 7 
7 Test the control circuit of the auxiliary air temperature actuator for an open, high resistance, short to ground or short to voltage. Refer to CIRCUIT TESTING and WIRING REPAIRS .
Did you find and correct the condition?		 - Go to Step 15  Go to Step 8 
8 Test the ground circuit of the auxiliary air temperature actuator for open or high resistance. Refer to CIRCUIT TESTING and WIRING REPAIRS .
Did you find and correct the condition?		 - Go to Step 15  Go to Step 9 
9
IMPORTANT: The auxiliary air temperature actuator connector and the auxiliary HVAC control module connector must be connected to correctly perform test.
  1. Turn ON the ignition, with the engine OFF.
  2. With the scan tool, observe the Aux. Mix Door Actual data parameter in the Auxiliary ECC Data list.
  3. Connect a 3-amp fused jumper wire between the control circuit and the 5 volt reference circuit of the auxiliary air temperature actuator. This drives the actuator to the full cold position.
  4. Remove and reconnect the jumper wire between the control circuit and the ground circuit of the auxiliary air temperature actuator. This drives the actuator to the full hot position.
Does the auxiliary air temperature actuator drive shaft rotate and do the counts change?		 - Go to Step 12  Go to Step 10 
10 Inspect the auxiliary air temperature door and the auxiliary air temperature actuator for the following:
  • Incorrectly installed auxiliary air temperature actuator.
  • Broken or binding linkages or auxiliary air temperature door.
  • Obstruction that prevents the auxiliary air temperature door from operating within it's full range of motion.

Did you find and correct the condition?		 - Go to Step 15  Go to Step 11 
11 Inspect for poor connections at the harness connector of the auxiliary air temperature actuator. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 15  Go to Step 13 
12 Inspect for poor connections at the harness connector of the auxiliary HVAC control module. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 15  Go to Step 14 
13 Replace the auxiliary air temperature actuator. Refer to AIR TEMPERATURE ACTUATORS - AUXILIARY .
Did you complete the replacement?		 - Go to Step 15  -
14 Replace the auxiliary HVAC control module. Refer to HVAC Control Module Replacement - Auxiliary .
Did you complete the replacement?		 - Go to Step 15  -
15
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 - Go to Step 2  System OK
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