Test J: Defrost System Is Inoperative

J1 - J6:

J7 - J13:

J14 - J18:

Normal Operation
Under normal operation the heated grid relay coil receives power when the ignition switch is in the ON position. The rear window defrost switch will then supply a ground signal when applied through circuit 1010 (DB/OG) to the Generic Electronic Module (GEM). Once the GEM receives input from the rear window defrost switch the GEM will then supply the ground to the heated grid relay for approximately ten minutes or until the rear window defrost switch is pressed again. The heated grid relay will then switch power from circuit 185 (BK) to circuit 186 (BN/LB) to power the rear window defrost grid. The rear window defrost grid is then grounded through circuit 57 (BK).

DTC B1345 will set if the input to the heated grid relay coil is shorted to ground.

DTC B1347 will set if the input to the heated grid relay coil is open or shorted to voltage.

Possible Causes
^ Circuit 1010 (DB/OG) open.
^ Circuit 185 (BK) open or short to ground.
^ Circuit 186 (BN/LB) open or short to ground.
^ Circuit 57 (BK) open.
^ Rear window defrost switch.
^ Heated grid relay.
^ Central Junction Box (CJB).
^ GEM.