I have a 2005 Expedition in which the rear latch won't lock. The doors and rear window lock and unlock, but the rear latch will not lock. I took the rear panel off and put a test light on the wires. There are two sets of wires and I tested both. One set has a wire that lights when I lock, but the other set didn't light at all. Does this look like a defective latch mechanism or should there be power to some of the other wires? Thanks in advance for your help.
Bruce