DTC 21/31, Courtesy Lights Feed (Circuit Shorted To Ground): Notes

BCM provides a 12-volt input to courtesy lights on courtesy lights feed circuit when commanded by instrument panel dimmer switch, left or right door jamb switch or hatch switch inputs.

DTC 21/31 will set when battery circuit is open due to a problem with COURTESY fuse No. 8, harness or connector; courtesy lights feed circuit is shorted to ground for more than 50 milliseconds while BCM is providing input on circuit; or BCM is defective.

When DTC 21/31 is set, courtesy lights will not illuminate and interior light switch will not operate. Glove box and center console lights will also be inoperative. DTC 21/31 will clear when fault is corrected and memory is cleared.

If DTC 31 is set, problem may be intermittent. Try to recreate fault while performing test by wiggling wiring and connectors. Check for poor connections at all connectors that may be causing intermittent condition.