A - No Communication With Lighting Control Module (LCM)

Pinpoint Test A - No Communication With Lighting Control Module

A1 - Check Circuit 195 (T/W) For Power

- Disconnect lighting control module connector C3.
- Using a voltmeter, measure for voltage at lighting control module connector pin C3-6, circuit 195 (T/W).

Is voltage B+?

YES GO to A5.
NO GO to A2.

A2 - Check Circuit 195 (T/W) For Short To Ground

- Remove fuse 4 (15A) from fuse junction panel.
- Using an ohmmeter connected to ground, measure resistance at lighting control module connector pin C3-6, circuit 195 (T/W).

Is resistance less than 10K ohms?

YES SERVICE circuit 195 (T/W) for short to ground. REPLACE fuse 4 (15A). RESTORE vehicle. RETEST system.
NO GO to A3.

A3 - Check Supply To Fuse 4 (15A)

- Remove fuse 4 (15A) from fuse junction panel.
- Using a voltmeter, measure for voltage at fuse 4 input cavity.

Is voltage B+?

YES GO to A4.
NO SERVICE supply to fuse 4 (15A). RESTORE vehicle. RETEST system.

A4 - Check Circuit 195 (T/W) For Open

- Using an ohmmeter, measure resistance of circuit 195 (T/W) between lighting control module connector pin C3-6 and output cavity of fuse 4 (15A).

Is resistance 5 ohms or less?

YES REPLACE fuse 4 (15A). RESTORE vehicle. RETEST system.
NO SERVICE circuit 195 (T/W) for open. RESTORE vehicle. RETEST system.

A5 - Check Circuit 54 (LG/Y) For Power

- Disconnect lighting control module connector C3.
- Using a voltmeter, measure for voltage at lighting control module connector pin C3-11, circuit 54 (LG/Y).

Is voltage B+?

YES GO to A9.
NO GO to A6.

A6 - Check Circuit 54 (LG/Y) For Short To Ground

- Remove fuse 8 (15A) from fuse junction panel.
- Using an ohmmeter connected to ground, measure resistance at lighting control module connector pin C3-11, circuit 54 (LG/Y).

Is resistance less than 10K ohms?

YES SERVICE circuit 54 (LG/Y) for short to ground. REPLACE fuse 8 (15A). RESTORE vehicle. RETEST system.
NO GO to A7.

A7 - Check Supply To Fuse 8 (15A)

- Remove fuse 8 (15A) from fuse junction panel.
- Using a voltmeter, measure for voltage at fuse 8 input cavity.

Is voltage B+?

YES GO to A8.
NO SERVICE supply to fuse 8 (15A). RESTORE vehicle. RETEST system.

A8 - Check Circuit 54 (LG/Y) For Open

- Using an ohmmeter connected to ground, measure resistance of circuit 54 (LG/Y) between lighting control module connector pin C3-11 and output cavity of fuse 1.

Is resistance 5 ohms or less?

YES REPLACE fuse 8 (15A). RESTORE vehicle. RETEST system.
NO SERVICE circuit 54 (LG/Y) for open. RESTORE vehicle. RETEST system.

A9 - Check Logic Ground For Open

- Using an ohmmeter connected to ground, measure resistance at lighting control module connector pin C3-9, circuit 676 (PK/O) Town Car or circuit 57 (BK) Crown Victoria, Grand Marquis.

Is resistance less than 5 ohms?

YES GO to Information Bus in Computers and Control Systems to diagnose network concern. Computers and Control Systems
NO SERVICE circuit 57 (BK) for open. RESTORE vehicle. RETEST system.