Test D: The Defrost System Is Inoperative

PINPOINT TEST D: THE DEFROST SYSTEM IS INOPERATIVE

D1-D4:

D4-D6:

D6-D8:

D9-D11:

Normal Operation
When the rear defrost switch on the electronic manual temperature control (EMTC) module is pressed, a signal is sent to the smart junction box (SJB) to ground circuit 1389 (WH). This closes the heated rear window relay, allowing voltage to be supplied to the heated rear window grid through circuit 186 (BN/LB). The heated rear window grid is grounded by circuit 1205 (BK).

Possible Causes
- circuit 186 (BN/LB) open
- circuit 298 (VT/OG) open
- circuit 1205 (BK) open
- circuit 1389 (WH) open
- circuit 1426 (PK) open
- heated rear window relay
- heated rear window switch
- heated rear window grid