G: Rear Window Will Not Defrost - Crown Victoria/Grand Marquis

Pinpoint Test G - Rear Window Will Not Defrost - Crown Victoria, Grand Marquis

NOTE: Ford DOES NOT provide a procedure to perform the following pinpoint test without the Rotunda New Generation Star (NGS) tester 007-00500 or equivalent.

G1 - Test Fuse 17 (10A)

- Put ignition switch in RUN.
- Press heated back window switch and light.
- Read voltage at fuse junction panel fuse 17 (10A).

Is there voltage at the fuse?

YES Go to G9.
NO CHECK HTD BLT in power distribution box and fuse junction panel fuse 17 (10A). Note that fuse 17 will only have power when rear defroster is active. If fuse is good, GO to G2.

G2 - Test Heated Back Window Output

- Probe back of connector pin C2-12 of lighting control module.
- Test for continuity with ground.

Is there continuity?

YES GO to G6.
NO GO to G3.

G3 - Test Heated Back Window Switch PID With Switch Inactive

- Connect Rotunda New Generation Star Tester 007-00500 or equivalent to data link connector.
- Request heated backlight switch status PID RDEF_SW.

Does PID indicate switch active?

YES SERVICE switch for stuck switch. SERVICE circuit 1010 (DB/O) for short to ground. RETEST system.
NO GO to G4.

G4 - Test Heated Back Window Switch PID With Switch Active

- While holding heated back window switch, request heated backlight switch status PID RDEF_SW.

Does PID indicate heated back window switch and light active?

YES GO to G5.
NO SERVICE heated back window switch and light. SERVICE circuit 1010 (DB/O) for open circuit. RETEST system.

G5 - Test Ignition Status

- Turn ignition switch to RUN.
- Request ignition switch status PID IGN_DD.

Does PID indicate ignition in RUN?

YES REPLACE lighting control module. RETEST system.
NO CHECK fuses 6 (15A) and 13 (5A). If both fuses are good, SERVICE circuits 296 (W/P) and 640 (R/Y). RETEST system.

G6 - Test Heated Back Window Relay Circuit

- Turn ignition switch off, then to RUN.
- Press heated back window switch and light
- Check for continuity at input to heated back window relay circuit 688 (GY/LB) with ground.

Is there continuity?

YES GO to G7.
NO SERVICE Circuit 688 (GY/LB). RETEST system.

G7 - Test Heated Back Window Feed

- Disconnect connector from heated back window relay.
- Read voltage at circuit 185 (BK) on connector (2 places).

Does voltage read B+?

YES GO to G8.
NO SERVICE circuit 185 (BK) RETEST system.

G8 - Test Heated Back Window Output

- Using a jumper wire, short circuits 185 (BK) and 186 (BR/LB) on relay connector together.

- Read voltage at fuse 17 (10A).

Is voltage reading B+?

YES REPLACE relay. RETEST system.
NO SERVICE circuit 186 (BR/LB). RETEST system.

G9 - Test Heated Back Window Indicator

- Make sure that heated back window is still on.

Is heated back window switch indicator lit?

YES GO to G10.
NO SERVICE heated back window switch and light. RETEST system.

G10 - Test Voltage On Circuit 186 (BR/LB)

- Make sure that rear defroster is still on.
- Read voltage on connector to hidden antenna module circuit 186 (BR/LB).

Is voltage reading B+?

YES GO to G11.
NO SERVICE circuit 186 (BR/LB). RETEST system.

G11 - Test Hidden Antenna Module

- Make sure that rear defroster is still on.
- Read voltage on output of hidden antenna module to heated back window.

Is voltage reading B+?

YES GO to G12.
NO REPLACE radio isolator module. RETEST system.

G12 - Test Grounds

- Check for continuity from vehicle ground to circuit 57 (BK) of radio isolator module.

Is there continuity?

YES GO to G13.
NO SERVICE circuit 57 (BK). RETEST system.

G13 - Test Radio Isolator Module

- Check for continuity to ground through the radio isolator module from the ground output to the heated back window.

Is there continuity?

YES REPLACE back window glass. RETEST system.
NO REPLACE radio isolator module. RETEST system.