H: Rear Window Defroster Will Not Auto. Shut Off - Town Car

Pinpoint Test H - Rear Window Defroster Will Not Shut Off Automatically - Town Car

H1 - Test Mirror Circuit

- Remove fuse 13 (10A).
- Test on output side of fuse for voltage.

Is voltage reading B+?

YES SERVICE circuit 59 (DG/P) for short to B+. RETEST system.
NO GO to H2.

H2 - Test Fused Feed Input

- Test for voltage on input side of fuse 13 (10A).

Is voltage reading B+?

YES GO to H3.
NO SERVICE radio isolator module.

H3 - Test Lighting Control Module

- Disconnect connector C4 from lighting control module.
- Test for voltage on input side of fuse 13 (10A).

Is voltage reading B+?

YES GO to H4.
NO REPLACE lighting control module. RETEST system.

H4 - Test Antenna Isolator Module

- Remove heated back window relay.
- Test for voltage on input side of fuse 13 (10A).

Is voltage reading B+?

YES SERVICE circuit 186 (BR/LB) for short to B+. RETEST system.
NO SERVICE radio isolator module. RETEST system.