Car Wiring

Spent yesterday identifying, labeling, and removing wiring. In retrospect I should have done this when the dash was removed...maybe. Near as I can tell they have all of the wiring in place for whatever options you might ever want installed in the car. This includes: A/C, power windows & locks, and sun roof motor. I focused on removing the unneeded wiring in the engine compartment. This isn't necessary since you can easily move the few connectors to the side or tie them out of the way, but I had some spare time and curiosity.

First off I'd like to say that I'm developing a deeper respect for all of the folks in the auto industry. How they design and jam all of this stuff into a car without ending up with pure chaos is beyond me. Just the wire bundle going from under the dash to the engine compartment is a good example. It starts around the fuse box area, makes a quick detour out through the left fender area, and resurfaces in the front left corner behind the headlights. Now we're talking a wire bundle with fifty or so wires all nicely wrapped together. Once it comes into the engine compartment it starts branching out: a couple wires to a side light, a few for headlights, a dozen or so to A/C relays which in turn bring some new ones back into the bundle, sensor wires for transmission neutral and reverse switches, tachometer, radiator fan, and more. These all exit and the remaining bundle is routed to the other side of the compartment. At the other side the rest of the wires branch out to lights, windshield fluid reservoir, alternator, A/C, and more sensors.

What I did was take this whole bundle apart and weed out all of the unused and unneeded wiring, cut them off near the fender, and put some heat shrink tubing and electrical tape on to protect and isolate them. I identified and labeled the wiring I may be interested in using: tachometer, transmission neutral, alternator power cable, a relay assembly switched on by the key, and a heavy gauge wire turned on by the key. Once all of this was done I cleaned up and rewrapped all of the wiring bundle, securing it out of the way again.

Once this was done I hooked up the battery and verified that everything worked. Had some problem with a couple of the circuits in the dash which I traced down to a big connector by the fuse block not fully seated. Boy, there is SO much wiring under the dash that clearly isn't being used, and probably even more that could be scrapped with a little research. It's tempting but I think I'll resist it this time (recent memories of removing/installing the dash are too vivid!). Still it feels good to have cleaned up what I did, always a good feeling when you can simplify something and in the process increase your level of understanding. I'd say that with the removal of the combustion engine and its sensors and control computer I've turned three pages of chassis electrical schematics down to one. Of course now I have my own new-fangled schematic for the motor and controller which easily fills a page.

Next: Piles of Plans