My 1994 was garaged for a good part of its life, so its electrical system is in reasonably good shape, even after 200,000K.

Suddenly I had a light out in the rear tail light assembly and traced it to the tailgate wire harness. The harness runs from the roof behind the left hinge to the tailgate where it feeds everything in the tailgate. Upon close examination I saw that three of the 5 wires were abraded to the degree that their coverings were gone and the copper wire was visible. At least one of these must have grounded against the car frame causing what appeared on the instrument panel as a bulb out. I pulled the harness enough to work on it wrapped the exposed wires and put everything back together. The bulb out condition was solved.

During the couple weeks it took me to get to the project, I noticed that my central door locking system had failed. I did not associate this problem with the tailgate wiring, but maybe I should have.

The symptoms, however, are most confounding. When I lift depress the drivers lock, I believe I am hearing activity at the tailgate lock and possibly the three other doors. But, that activity is not sufficiently vigorous to engage the locks. So, I’m thinking and thinking and came up with this, but realized it could not be. Let me try anyway.

When I examined the three exposed wires in the tailgate harness I noticed that two remained quite robust, that is lots of fine wires making up the flexible cable remained. One of the wires however was rather anemic. At the time, I assumed, either a) it was a smaller gauge wire to begin with, or b) it had abraded away ½ its wires content, but there was enough left, so it wouldn’t matter.

When the door locking problem presented itself, I want back and reconsidered. Perhaps the anemic wire was the very one that served the tailgate lock and thus it is transferring enough voltage to activate the actuator in the lock assembly, but not enough to cause the actuator to engage the lock into its striker. I still like this theory, but a wise friend has made me doubtful. Here are two reasons, why.

First, even if the suspect anemic wire was the one serving the tailgate lock, that might explain why that lock was not functioning fully, but it doesn’t explain why the other three doors are not functioning.

Second, the doors locks were functioning before I started to fiddle around with the tailgate harness. (Could I have somehow promoted the critical point where the wires were good enough to carry the necessary voltage, but my work on the wires pushed the anemia to a point where there was not sufficent voltage being transferred.

Finally, it is possible I caused something in the system to burn out when I was working on the harness. I regret now, I did not disconnect the battery. On the other hand, everything I can think of in the tailgate (with the possible exception of the center brake light) only functions through a switch and the swithces (wiper, license plate lights, window heater) were off.

I suppose I could start by just replacing the entire harness, now that I know how to access it. It would be very disappointing to do so and find it had nothing to do with the problem.

The baffling aspect of this problem is that the actuators seem to be functioning, but not functioning fully to engage or disengage the locks.

Note: The hazard lights are on the same fuse #2 and they are working fine. So I know its not a fuse. Besides, the driver's door lock is having some electrical effect on the others. Sorry to repeat.

Bob Franklin