How about this for a puzzle. The rear window de-mister was not working on my Toyota Supra MK3, so I checked the voltage at the terminals and got reading of 12volts. So I suspected that the element had gone , checked it out and all was o/k. Next I thought, right, I will put a test lamp on the terminals and it did not light. This was a real puzzle, how can you have 12volts and no power to light a very small bulb ?. I next checked the wiring by stripping a small part of the insulation off, and it was black. The only conclusion that I can come to is that the black wire has set up a very high resistance and cannot pass any current but still gives a reading of voltage. Unless anybody has any experience of this and knows better?. Your suggestions will be of great assistance. As an aside I bypassed the positive wiring with a new wire temporarily to test this theory and the heater worked and also lit up the test lamp using the old negative wire and the new positive.Interesting eh. Peter
- posted
20 years ago