FB - Individual Backup Lamp Inoperative

Pinpoint Test FB: Individual Backup Lamp Inoperative

FB1 - Check Switch Output

- Turn ignition switch to RUN. Do not start vehicle.
- Actuate shift lever to the REVERSE position.
- Using a voltmeter connected to ground, check circuit 140 (BK/PK) for voltage at TR sensor pin 3.

Is voltage B+?

YES G0 to FB2.
NO REPLACE damaged transmission range (TR) sensor. RESTORE vehicle. RETEST system.

FB2 - Check Supply To Backup Lamps

- Gain access to backup lamps as outlined.
- Disconnect backup lamp miniature bulb.
- Using a voltmeter connected to a known good ground, check circuit 140 (BK/PK) for voltage.

Is voltage B+?

YES GO to FB3.
NO SERVICE circuit 140 (BK/PK) for open circuit. RESTORE vehicle. RETEST system.

FB3 - Check Backup Lamp Ground

- Using an ohmmeter connected to a known good ground, connect second lead to circuit 57 (BK) at backup lamp socket. Measure resistance.

Is resistance 5 ohms or less?

YES REPLACE damaged backup lamp miniature bulb. RESTORE vehicle. RETEST system.
NO SERVICE circuit 57 (BK) for open circuit. RESTORE vehicle. RETEST system.