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Diagnostic Aids

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Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

DTC B3874

Step Action Yes No
Schematic Reference: Wiper/Washer System Schematics 
Connector End View Reference: Master Electrical Component List in Wiring Systems
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Turn the ignition to the ON position.
  2. On the wiper switch, select a low speed.
Do the windshield wipers operate?		 Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3
  1. Turn the ignition to the OFF position.
  2. Turn the wiper switch OFF.
  3. Remove the WPR1 relay from the underhood fuse block.
  4. Using a test lamp connected to ground, probe the WPR1 relay control circuit at the underhood fuse block.
Does the test lamp illuminate?		 Go to Step 8  Go to Step 4 
4
  1. Leave the test lamp connected.
  2. Turn the ignition to the ON position.
  3. Turn the wiper switch to a low position.
Does the test lamp illuminate?		 Go to Step 5  Go to Step 6 
5
  1. Turn the wiper switch to the OFF position.
  2. Turn the ignition to the OFF position.
  3. Using a test lamp, probe the WPR1 relay control circuit and the ground circuit of the WPR1 relay at the underhood fuse block.
  4. Turn the ignition to the ON position.
  5. Turn the wiper switch to a low position.
Does the test lamp illuminate?		 Go to Step 9  Go to Step 7 
6 Test for a poor connection, an open or short to ground in the WPR1 relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 10 
7 Test for a poor connection or an open in the ground circuit of the WPR1 relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 11 
8 Repair a short to battery positive voltage in the WPR1 relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 12  -
9
  1. Replace the WPR1 relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems.
  2. Operate the vehicle within the Conditions for Running the DTC.
Does the DTC reset?		 Go to Step 11  Go to Step 12 
10 Replace the body control module (BCM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.
Did you complete the replacement?		 Go to Step 12  -
11 Replace the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.
Did you complete the replacement?		 Go to Step 12  -
12
  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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