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August 2010 Randy's Electrical Corner

Posted in How To: Electrical on August 1, 2010
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So there I was, helping to wire up some heated seat covers, but with a twist.

I've drawn this diagram and called out the stuff I added and other things that might not be totally clear. The red arrow is the way the electricity was flowing with the bad ground, and the green arrow the way it flowed once I fixed the problem.

Instead of using one switch for both back and bottom, I wired them up for independent use (one switch for bottom, one for back). These were nice little switches with a light when turned on. Lights in switches need a ground and a positive to light up. I daisy-chained the ground wires on all the switches for a clean installation.

Needless to say, it didn't work out the way I had planned it. If it did, this would be a boring column and you wouldn't learn anything from my mistakes.

Bad grounds are the most common cause for weird electrical issues, so I should have known what was going on. However, I told my friend how I wanted the ground wires run, so there should be no issues. Problem is, he didn't listen to me, and I was sitting there drawing wiring diagrams and thinking diode thoughts to stop power back feeding. Diodes are the one-way valve of the electrical world and in rare situations they can be used to stop electricity flowing in the wrong direction. I've used them before in a couple of flatfenders with great success and was thinking that maybe this was one of those rare times.

I don't understand what the heating element is made out of as well as I should. I just figured it was a resistor that simply got hot when electricity flowed through it. In this case, the problem wasn't my lack of understanding the heating element-I forgot the most important thing.

I forgot the cardinal rule of automotive electronics: If something isn't doing what it is supposed to do, check the ground. Had I remembered that from the beginning, I wouldn't have worked out a fix with diodes to fix a problem I didn't have.

So here are a few helpful hints on grounding, and the diagram of what I was dealing with, so you can get a chuckle at my wanting to use a bunch of diodes to fix a bad ground.

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