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Test Description

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The number(s) below refer to the step number(s) on the diagnostic table.

  1. 2:  Listen for an audible click when the after blower relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3:  Tests for voltage at the coil side of the after blow relay. The BATT Feed fuse supplies power to the coil side of the after blow relay.
  3. 4:  Verifies that the body control module is providing ground to the after blow relay.
  4. 5:  Tests if ground is constantly being applied to the after blow relay.
  5. 6:  Tests if intermittent voltage is being applied to the after blow relay.
  6. 12:  It is important to follow the programming procedure for replacing the body control module.
DTC B3787

Step Action Yes No
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 - Manual 
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the after blow relay ON and OFF.
Does the after blow relay turn ON and OFF with each command?		 Go to Diagnostic Aids Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the after blow relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the battery positive voltage circuit of the after blow relay with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 Go to Step 4  Go to Step 10 
4 
  1. Connect a test lamp between the control circuit of the after blow relay and the battery positive voltage circuit of the after blow relay.
  2. With a scan tool, command the after blow relay ON and OFF.
Does the test lamp turn ON and OFF with each command?		 Go to Step 8  Go to Step 5 
5  Does the test lamp remain illuminated with each command? Go to Step 7  Go to Step 6 
6  Test the control circuit of the after blow relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 9 
7 Test the control circuit of the after blow relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 9 
8 Inspect for poor connections at the after blow relay. 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 13  Go to Step 11 
9 Inspect for poor connections at the harness connector of the body 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 13  Go to Step 12 
10 Repair the battery positive voltage circuit of the after blow relay. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 13  -
11 Replace the after blow relay.
Did you complete the replacement?		 Go to Step 13  -
12 
IMPORTANT: Perform the set up procedure for the body control module.
Replace the body control module. Refer to Body Control Module Replacement in Body Control Systems.Did you complete the replacement?		 Go to Step 13  -
13
  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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