Back Up Alarm Sounds When Using RKE To Unlock Doors - keywords entry keyless lamp light lighting lock perimeter remote reverse

This PIis Being Updated To Add Additional Correct Information. Please discard PIT4075.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some owners may comment that the back up alarm RPO 8S3, will sound when unlocking the doors with the RKE remote. With the new 6-speed Allison Transmission RPO MW7, a change was made in the electrical architecture that could cause this concern. If the perimeter lighting is on and the ambient light sensor senses a low light condition when the RKE remote is used to unlock the doors, the reverse lights turn on which in turn sounds the back up alarm.

To correct this concern turn off the perimeter lighting feature on vehicles with DIC control buttons or install an isolation relay in-line to the back up alarm per the procedure below.

Install an isolation relay, part number 12167112 in-line to the back up alarm. Connect the relay in the following manner:

Cut circuit 1624 Lt Grn going to the back up alarm and install one cut end to pin 87 and the other cut end to pin 30 of the relay. Ground pin 85 of the relay and provide a fused hot in run 12 volt power to pin 86 of the relay.

Note: The easiest place to install the relay is at the UBEC.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.