F150 Interior Lights Won't Go Out
I’ve had a running battle with 1999 F150 XLT dome and cargo lights failing to shut off when the door is closed. There is also the instrument panel warning light indicating that the door is not closed. I had the driver side door switch professionally replaced, but this only helped for a short while. The problem returned on hot (~90F) days. I complained to the mechanic but he did not know what else to do. I then took the door and latch apart to figure it out. My take was that the mechanic used too much grease on the connector. It was cleaned and put back together with some improvement, but the problem eventually returned with hot weather. I can hear the click of some component deep in the dash after the door closes and when the dome and warning lights finally turn off. Interim repairs have been swapping the relays in the interior fuse-relay panel, disconnecting the battery, and removing the interior lamp relay (Relay 1) during the hot weather (best method). The generic wiring diagrams I’ve looked at so far indicate that the component feeding power to the interior lamp relay is the generic electronics module. That may be replaced next if it can be accessed without removing the whole dashboard. I was clued in to heat sensitive Ford relays when the starter motor seemed to fail on a very hot day. The starter motor was professionally replaced, but the problem returned as soon as it got hot outside. I replaced the started solenoid and the problem disappeared. Good luck…I will add to this thread once I get it figured out.