Exterior Lights Diagnosis Back Up Lamps

Fuses

Location: UHJB

Type: 10A Minifuse

Feeds: Circuit 239 and 239A

If the following systems are operating normally, the fuse is most likely good:

• Backup Bulbs
• Coolant Level Switch

If the fuse is blown, determine the cause of the blown fuse and repair.

Replace the fuse as needed.

Grounds

Before checking the ground circuit from the faulty component all the way to the ground stud, check the circuit from the splice pack to ground by testing some of the other subsystems grounded by the same splice pack. If the other subsystems function properly, it is most likely that the path from the splice pack to ground is good, or at least one of the paths is good with redundantly grounded splice packs.

The left rear body ground splice pack provides a ground path for the rear body and hatch harness. If one of the following systems is operating normally the ground circuit is most likely good:

• License, CHMSL, cargo lamps
• Fuel pump
• Washer pump

Check for OPENS/SHORTS.

Repair as needed.

Components

Park/Neutral Switch (Back-up Switch) (Auto Trans Only)
1. Check switch resistance.
Switch resistance: OPEN when PRNDL not in Reverse. Less than one ohm when PRNDL in Reverse.
2. Repair/replace as needed.

Back Up Switch (Manual Trans Only)
1. Check switch resistance.
Switch resistance: OPEN when trans not in Reverse. Less than one ohm when PRNDL in Reverse.
2. Repair/replace as needed.

Bulb Socket
1. Check voltage through the bulb socket.
2. Check for damaged or corroded terminals or connectors. Check terminals for tightness.
3. Repair/replace as needed.