Test K: The Defrost System Will Not Shut Off Automatically

PINPOINT TEST K: THE DEFROST SYSTEM WILL NOT SHUT OFF AUTOMATICALLY

K1-K2:

Normal Operation
The heated backlight relay, which is integral to the smart junction box (SJB), receives power from circuit SBB06 (BN/RD). When the rear window defrost switch is pressed on the electronic automatic temperature control (EATC) or electronic manual temperature control module (EMTC) control unit, a message is sent to the SJB through circuit CH122 (WH/OG). Once the SJB receives the message to turn on the rear window defrost, the SJB grounds the heated backlight relay coil, which sends power through the antenna module to the rear window defrost grid through circuit CLS38 (VT/WH).

Possible Causes
- Circuit CLS38 (VT/WH) shorted to power
- Antenna module
- Inoperative SJB