Circuit/System Testing

DTC B370B

1. Ignition OFF and all vehicle systems OFF, disconnect the KR7 Rear Wiper Relay. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 Ω between the ground circuit terminal listed below and ground.
   • Terminal 86
   • Terminal 87A
   • If 10 Ω or greater 
   1. Ignition OFF.
   2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
   • If less than 10 Ω 
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 87 and ground.
   • If the test lamp does not illuminate and the circuit fuse is good 
   1. Replace the X50A Fuse Block - Underhood.
   • If the test lamp does not illuminate and the circuit fuse is open 
   1. Ignition OFF, remove the test lamp. Disconnect the harness connector at the M45 Rear Wiper Motor.
   2. Test for infinite resistance between the terminal 30 control circuits and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the KR7 Rear Wiper Relay
5. Ignition ON, connect a test lamp between the control circuit terminal 85 and the ground circuit terminal 86.
6. Verify the test lamp turns ON and OFF when commanding the Rear Wiper Relay Active and Inactive with a scan tool.
   • If the test lamp is always OFF 
   1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module.
   2. Install a 3 A fused jumper wire between the control circuit terminal 10 X4 and B+.
   3. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
   4. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
   • If the test lamp is always ON 
   1. Ignition OFF, remove the test lamp, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON.
   2. Test for less than 1 V between the control circuit terminal 10 X4 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K9 Body Control Module.
   • If the test lamp turns ON and OFF 
7. Test or replace the KR7 Rear Wiper Relay