Test M: The Defrost System Is Inoperative

PINPOINT TEST M: THE DEFROST SYSTEM IS INOPERATIVE

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 HVAC module - electronic automatic temperature control (EATC) or HVAC module - electronic manual temperature control module (EMTC), 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 to the rear window defrost grid through circuit CLS38 (VT/WH).

- DTC B1345 Heated Backlite Input Circuit Short To Ground - Switch input shorted to ground

This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Inoperative SJB
- Inoperative HVAC module - EATC or HVAC module - EMTC

M1-M4:

M4-M6:

M6-M8:

M8-M9: