Rear Lamp Failure

[bassguitarlover5]

i have a 93 grand cherokee and my computer is telling me that my rear lamps are failing...which is a lie. all three of the lights work fine. but the weird part is that the warning comes on at random times. sometimes when im braking and even sometimes when im accelerating. is anyone else having this problem?
alex

[hardisk_c]

If you haven't done so already, check the base of the bulbs and the sockets for corrosion, or even just a loose connection. The sensor bases its reading off of resistance in the circuit, and a too low/high reading will trip the sensor.

[dksob81]

The Lamp outtage module - the reason for your REAR LAMP FAILURE, monitors the brake light bulbs (2 side and 2 high mount), tail light bulbs, Reverse light bulbs, license plate bulbs, rear side marker bulbs and front side marker bulbs.

Check to make sure they are all working properly....

Joe

[JOE RILLA]

I had the same problem on my '94. All the bulbs worked fine but the bulb failure message kept coming on. Turns out I had the wrong bulb in the 3rd brake light. they looked right and worked fine but were not the correct #bulb. I had a #921 instead of a #912 exact same bulb but slightly different resistance so it tripped the sensor. Check the owners manual for the correct part #'s and then check all your bulbs to make sure they are right.

[xj31]

If all the bulbs are ok check the connectors for the harnesses that go to the tail lights.They are in the quarter panels and on 93s they had a tendency to corrode.there was a bulletin to replace the harnesses and connectors,but you might have a hard time getting parts and you could just cut the connectors off and solder the wires if that is it.
heres the bulletin:
NO: 08-31-93
SUBJECT: Tail Lamp Harness Corrosion
DATE: Jul. 16, 1993
SYMPTOM/CONDITION:
Inoperative tail, stop, back up or side marker lights or a "rear lamp failure" display in the Vehicle Information Center.

DIAGNOSIS:
Remove the tail lamp assemblies and inspect the six way connector terminals for any signs of corrosion or discoloration of the terminals. If signs of corrosion are present, perform the repair procedure.

PARTS REQUIRED:
Quantity
Description
Part No.

1

Harness Repair Package
4761589



REPAIR PROCEDURE:
This bulletin involves replacing both tail lamp harnesses and installing six way connectors to the body harness.

Disconnect the negative battery cable.
Remove both tail lamp assemblies and install the right and left side harnesses listed above transferring the bulbs.
Strip away 6 inches of the harness tape on the body harness and cut the six way connectors out of the body harness, staggering the wire cuts by 1/2 inch. Slide a piece of heat shrink tubing over each of the wires. Strip off 1 inch of insulation from each of the wires on the replacement six way connectors. Twist the wires together following the color codes on the wire insulation. Using rosin core solder, solder the wires from the connectors supplied to the body harnesses.
Shrink the heat shrink tubing over the repaired area using a heat gun. Re-tape the body harnesses using vinyl electrical tape.
Install the tail lamp assemblies.
Connect the negative battery cable.
POLICY:
Reimbursable within the provisions of the warranty.

TIME ALLOWANCE:
Labor Operation No.
Time

08-90-75-90
1.2 Hrs.



FAILURE CODE:
Code
Description

21

Connection Defect