91 Vette wiring issue
 

I'm working on a family friend's vette trying to figure out where his electrical issue is because I have some background in car electronics. so here's the problem.
Car won't make a noise. no door chime, no lights on the dash nothing. we had previously thought the battery was pooched and had something to do with the stereo he had professionally installed a few years back.We bought a new battery this morning.
I disconnected the stereo from the battery. nothing. I disconnected his factory alarm. still nothing.
I get to the ignition wires and they're all in tact with the except of where the installers made the neccessary connectionsfor thealarm - but it's disconnected so it wouldn't have an effect either way.
I begin testing the wires only to find that thechassissomehow has a full charge- 12.71 volts. is this something that happens frequently in 91 vettes or is this something that none of you have heard of.
- keep in mind that if it was just a short there would be no voltage at all.

if you guys could help I would be in your debt and my friend would even more grateful.

RE: 91 Vette wiring issue
 

First things first, check every fuse with a test light using theground on the battery, then hook up the test light to the positive on the battery and see if you have a ground in the car, like the cigarette lighter casing. If you do, check battery voltage at the battery and make sure you have the same voltage at the fuse panel. There is a junction block behind the battery where a connection might be lost as well as a ground on the block near the oil filter. If you have a drop of 1 volt anywhere, different than your batteryyou have a poor connection. Once you have power in the car and the engine won't crank over, that could be the contact in your ignition switch that has to make contact with the resistor on the key, which is a common problem. If you wish to take this step by step, my email is abettigole@charter.net I have 35 years under my belt fixing electrical and mechanical problems, hope this helps.