As mentioned in a previous post I am (finally) re-doing the front door cards. Since this exposes the guts of the door it’s the obvious time to check out the wiring.
There is quite a bit of wiring in the front doors – power windows, power window switch (and connection to the master power window switch in the drivers door), and the infamous courtesy light. Plus the new power and ground wires I added to drive the electric windows reliably.
The wiring harness looked good. It always looks good. If it doesn’t look good I replace it! But there was something strange in the wiring to the power window switch… The wires weren’t exactly what was called out in the Factory Service Manual. Time to remove the tape protecting the harness and see what was going on.
Under the tape was a folded piece of wire not connected to anything else. Just sitting there. Strange! No idea what that was all about. With that wire out of the way the rest of it made more sense.
Anticipating working on the wiring harness inside the door I finally broke down and bought the right tool for the job – Tessa Tape. This tape is made specifically for wrapping wiring harnesses. It is made of cloth to be abrasion resistant. It has a special adhesive that sticks to the tape but not much else – unlike regular electrical tape which leaves sticky adhesive residue all over everything. Tessa Tape is a complement to electrical tape – electrical tape insulates and Tessa Tape is for wrapping wire bundles.
Using the Tessa Tape I re-wrapped the wire bundles I had opened up. I also wrapped the wiring harness where it entered the door to provide additional abrasion resistance and protection for the wires.
While it was on the workbench I took a close look at the socket for the courtesy light. Hmm, it looks like the spring loaded prongs that make electrical contact with the bulb are close to the shell. Wait a minute – what if one of the contacts has worn just enough that it can sometimes make contact with the shell of the socket?
There was the time that touching the socket to the door frame would cause the light to come on. I blamed the LED bulb I was using for the problem – replacing the LED with a regular bulb caused the problem to go away (at that time…). What if the problem wasn’t the LED but instead one of the contacts?
This is simple enough to fix – insulate the shell from any possible way of touching the contacts. A strip of plastic inside the socket would do the trick. I had some mylar drafting film that was perfect for this. Cut a strip just wide enough to barely touch the base of the bulb when the bulb is installed and slip it inside the socket.
I’ve been suspicious for quite a while that there were actually multiple issues with the courtesy lights and that I was seeing different issues at different times. The combination of problems with the door switch and the light socket would seem to cover just about everything I’ve seen. Hopefully the problem is finally fixed!