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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 >> DTC B0145, B0428, or B3531: Mode/Temperature Actuator >> Test Description

Test Description

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

  1. 2:  If more than one DTC is set, observe all of the Door Actual parameters for each corresponding DTC. If the door actual parameter is not out of range, then the concern is with the control portion of the actuator.
  2. 7:  The purpose of this step is to try to determine which actuator is internally shorted or if the auxiliary HVAC control module is creating the fault. After DTC are cleared, it can take up to 4 minutes for DTC to set.
  3. 8:  After DTC are cleared, it can take up to 4 minutes for DTC to set. The purpose of this step is to try to determine which actuator is internally shorted or if the auxiliary HVAC control module is creating the fault. If both DTCs return the auxiliary control module is internally shorted.
  4. 10:  The purpose of this step is to try to determine which actuator is internally shorted or if the auxiliary HVAC control module is creating the fault. After DTC are cleared, it can take up to 4 minutes for DTC to set.
  5. 11:  After DTC are cleared, it can take up to 4 minutes for DTC to set. The purpose of this step is to try to determine which actuator is internally shorted or if the auxiliary HVAC control module is creating the fault. If both DTCs return the auxiliary HVAC control module is internally shorted.
  6. 14:  If the scan tool does not display all three DTC, then the answer is No.
  7. 15:  If the scan tool does not display both DTC, then the answer is No.
  8. 17:  This step tests the low reference circuit.
  9. 18:  If the fused jumper opens, then the appropriate signal circuit is shorted to a power.
  10. 19:  If the scan tool parameter reads lower than 5 counts then the appropriate signal circuit is shorted to a ground.
  11. 20:  This step tests the 5-volt reference circuit. Test can be done with any auxiliary actuator. The auxiliary air temperature actuator can be accessed the quickest.
  12. 22:  If the scan tool displays one DTC when an actuator is disconnected, then the actuator that was disconnected is the area of the fault.
  13. 29:  The procedure for both auxiliary mode actuators are within the same replacement procedure.
  14. 30:  After a circuit repair, a recalibration of the actuators must be performed to ensure proper performance from the auxiliary HVAC system.
DTC B0145, B0428, or B3531

Step Action Values Yes No
Schematic Reference  : HVAC Schematics 
Connector End View Reference HVAC Connector End Views 
1 Did you perform the HVAC Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - HVAC Systems - Automatic 
2 
  1. Install a scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. With the scan tool, observe the appropriate Door Actual Parameter in the Rear HVAC/RSA data list.
Is the parameter within the calibrated range value?		 20-235 counts Go to Step 3  Go to Step 14 
3 With the scan tool, observe the Rear HVAC/RSA DTCs.
Does the scan tool indicate that only one of the following DTCs are present B0145, B0428, B3531?		 - Go to Step 12  Go to Step 4 
4 Does the scan tool indicate that DTCs B0145 and B3531 are set? - Go to Step 9  Go to Step 5 
5 Does the scan tool indicate that DTCs B0145 and B0428 are set? - Go to Step 6  Go to Diagnostic Aids
6 Test the auxiliary actuator door control circuit of the auxiliary HVAC actuators for the following conditions:
  • A short to ground
  • A short to voltage
  • A high resistance
  • An open

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 7 
7 
  1. With the scan tool, clear all DTCs.
  2. Disconnect the auxiliary air temperature actuator.
  3. Wait 4 minutes for DTC to set.
  4. With the scan tool, observe the Rear HVAC/RSA DTCs.
Does DTC B0145 return along with B0428?		 - Go to Step 8  Go to Step 27 
8 
  1. Reconnect the auxiliary air temperature actuator.
  2. With the scan tool, clear all DTCs.
  3. Disconnect the auxiliary mode actuator.
  4. Wait 4 minutes for DTC to set.
  5. With the scan tool, observe the rear HVAC/RSA DTCs.
Does DTC B0428 return along with B0145?		 - Go to Step 26  Go to Step 27 
9 Test the auxiliary mode door control circuit of the auxiliary console and auxiliary mode door actuator for an open, short to ground or short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 10 
10 
  1. With the scan tool, clear all DTCs.
  2. Disconnect the auxiliary mode actuator.
  3. Wait 4 minutes for DTC to set.
  4. With the scan tool, observe the rear HVAC/RSA DTCs.
Does DTC B3531 return along with B0145?		 - Go to Step 11  Go to Step 27 
11 
  1. Reconnect the auxiliary mode actuator.
  2. With the scan tool, clear all DTCs.
  3. Disconnect the auxiliary console actuator.
  4. Wait 4 minutes for DTC to set.
  5. With the scan tool, observe the rear HVAC/RSA DTCs.
Does DTC B0145 return along with B3531?		 - Go to Step 26  Go to Step 27 
12 Test the appropriate circuits for the DTC.
  • DTC B0145 test the following circuits:
    • The auxiliary mode door control circuit for an open between the splice and auxiliary mode actuator
    • The auxiliary actuator door control circuit for an open between the splice and auxiliary mode actuator
    • The 5-volt reference circuit for an open between the splice and auxiliary mode actuator
  • DTC B0428 test the following circuits:
    • The auxiliary air temperature door control circuit for an open, short to ground or short to voltage
    • The auxiliary actuator door control circuit for an open between the splice and the auxiliary air temperature actuator
  • DTC B3531 test the following circuits:
    • The console mode door control circuit for an open, short to ground or short to voltage
    • The auxiliary mode door control circuit for an open between the splice and the console mode actuator

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 13 
13 -
  1. Change the appropriate auxiliary switch position.
  2. With the scan tool, observe the commanded door position for the appropriate actuator.

Does the commanded position change with each selection?		 - Go to Step 27  Go to Step 26 
14  With a scan tool, observe the rear HVAC/RSA DTC List.
Does the scan tool display DTC B0145, B0428 and B3531?		 - Go to Step 20  Go to Step 15 
15  Does the scan tool display B0145 and B0428? - Go to Step 20  Go to Step 16 
16
  1. Disconnect the appropriate auxiliary actuator.
  2. Measure the voltage of the 5-volt reference circuit of the appropriate actuator to a good ground.
Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.Does the voltage measure near 5 volts?		 - Go to Step 17  Go to Step 21 
17 
  1. Disconnect the appropriate auxiliary actuator.
  2. Measure the voltage of the 5-volt reference circuit to the low reference circuit of the appropriate auxiliary actuator.
Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.Does the voltage measure near 5 volts?		 - Go to Step 18  Go to Step 24 
18 
  1. Connect a 3-ampere fused jumper between the low reference circuit and the signal circuit of the appropriate auxiliary actuator.
  2. With a scan tool, observe the appropriate Door Actual parameter in the rear HVAC/RSA data list.
Does the scan tool indicate that the appropriate Door Actual parameter is near 0 counts?		 - Go to Step 19  Go to Step 25 
19  Disconnect the appropriate auxiliary actuator.
Does the scan tool indicate that the appropriate Door Actual parameter is over 245 counts?		 - Go to Step 27  Go to Step 25 
20 
IMPORTANT: Ensure that the auxiliary air temperature actuator connector is connected during this step in order to avoid misdiagnosis. Test can be done with any auxiliary actuator. The auxiliary air temperature actuator can be accessed the quickest.
Measure the 5-volt reference circuit at the auxiliary air temperature actuator to a good ground.Refer to Circuit Testing in Wiring Systems.Does voltage measure near 5 volts?		 - Go to Step 23  Go to Step 21 
21 Test the 5-volt reference circuit of the auxiliary HVAC actuators for the following conditions:
  • A short to ground
  • A short to voltage
  • A high resistance
  • An open

Refer to Circuit Testing in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 22 
22 
IMPORTANT: Each actuator must be disconnected and connected one at a time to ensure misdiagnosis does not occur.
  1. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, observe the rear HVAC/RSA DTC List.
  3. Disconnect each auxiliary HVAC actuator one at a time.
Does the scan tool display DTC B0145, B0428 and B3531?		 - Go to Step 26  Go to Step 27 
23 Connect a test lamp between the battery positive voltage circuit of the auxiliary HVAC control module and the low reference circuit of the auxiliary air temperature actuator.
Does the test lamp illuminate?		 - Go to Step 26  Go to Step 24 
24 Test the low reference circuit of the auxiliary HVAC actuators for a high resistance or an open.
Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 26 
25 Test the appropriate signal circuit of the auxiliary HVAC actuators for the following conditions:
  • A short to ground
  • A short to voltage
  • A high resistance
  • An open

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 26 
26 Inspect for poor connections at the harness connector of the auxiliary HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 29 
27 Inspect for poor connections at the harness connector of the appropriate auxiliary HVAC actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 30  Go to Step 28 
28 Replace the appropriate auxiliary HVAC actuator. Refer to one of the following procedures:
Did you complete the replacement?		 - Go to Step 30  -
29  Replace the auxiliary HVAC control module. Refer to HVAC Control Module Replacement - Auxiliary .
Did you complete the replacement?		 - Go to Step 31  -
30  Recalibrate the actuators. Refer to Re-Calibrating Actuators (Primary) Re-Calibrating Actuators (Auxiliary HVAC) .
Did you complete the procedure?		 - Go to Step 31  -
31
IMPORTANT: Ensure to test system for 2 minutes after clearing DTC to avoid misdiagnosis.
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC.
Does the DTC reset?		 - System OK Go to Step 2 
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