750mV from battery to ground, Tracing the short: any usual suspects? Options

[Prospectfarms]

Key off. Red terminal to body gives somewhere between 1V and 750mV. (IMG:style_emoticons/default/sad.gif) To me that seems like a bare wire short to ground but I'm not an expert.

Likely spots? Anyplace I could test first before tracing the whole electrical system?

How about a short (N.P.I.) list of always-hot wires in the car. Doesn't have to be comprehensive -- just looking for a starting point.

Thanks.

[Mike Bellis]

The voltage you are reading could be capacitance from the ECU, coil or radio. Really the way you are testing will tell you nothing. You need to do a current test is you are worried about drain. 750mV is nothing and as long as you have electrical loads in the car, your test will tell you no valuable information. Remove the switch to test it properly. If you had a real direct short, your voltage reading would be 12V and not 1V.

I think you are worried for nothing.

20+ years of electrical troubleshooting experience.

[Prospectfarms]

The voltage you are reading could be capacitance from the ECU, coil or radio. Really the way you are testing will tell you nothing. You need to do a current test is you are worried about drain. 750mV is nothing and as long as you have electrical loads in the car, your test will tell you no valuable information. Remove the switch to test it properly. If you had a real direct short, your voltage reading would be 12V and not 1V.

I think you are worried for nothing.

20+ years of electrical troubleshooting experience.

O.K., its all becoming clear now. The coils, capacitors and such on that car act like small batteries, in a way, so their voltage will come across. A short, on the other hand will read the same voltage as the supply (battery) even it it's a tiny cut on the thinnest wire in the harness. I saw 1V, not 12V, so probably no short.

If a bare wire is finding ground I'd see 12V. The severity of the short, if any, would be read on the mA setting of the meter. That would tell me how much current is coming across. mA is "milliamps" or thousandth of an amp, no?

It is so fun when the haze clears and a little understanding sets in.
A lot of nice people with huge expertise have chimed in. Thank you all so much!

I'll keep testing...