Monday, June 25, 2007

Electrical Systems

To say I'm a neophyte when it comes to electrical systems is to state the obvious. This is made even a further embarrassment given my chosen profession is software engineering. It is true that I had to take 3 semesters of physics and even several computer hardware classes -- all I can remember is my English-as-a-second-language professor mispronouncing the term SR-Flip Flop. At any rate, I was in Barnes and Nobles the other day and picked up Haynes Techbook Automotive Electrical Manual.

In the manual, there is a primer on simple electrical circuits, and just exactly how the circuits are formed and work, and specifically why they fail. The reason I bought the book was a section on diagnosing directional signals and it really made some things clear. The LeMans came to me with the front directional signal covers, lights, socket and brackets in a box in the trunk. The previous owner had every intention of rewiring the lights, as the bulb sockets were new; just never got around to it I guess. At any rate, if you look the picture below, you'll see something interesting. If you click on it, you can see the wiring better.

Since this is a single-bulb directional light, the bulb actually has two filaments, and needs two hot wires -- one for the flasher signal, but one also for the headlights. This looks perfect above as there is two "hot" wires, however when the right directional or lamp was illuminated, the wires would smoke and sizzle; an obvious short. At any rate, the top left wire with the blue connector is actually a ground wire running to the body! The only reason I could think that these would be wired this way is that they wanted to keep the wires out of the way, either during paint, or God knows why! At any rate... that's enough for today... except I'd like to show you another picture of wiring in the car... you just never know what you're going to find.

If you notice in the red ellipse, just a small problem with the wiring insulation.

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