Where is the computer located on a 1996 Chevy Cavalier?
My car is about 1/2hr away from me, because when I got the work this morning it wouldn't start again. It was fine until I parked it.
I went to start it and nothing, no dash lights, no noises, no dinging key noise. So I left if for the day since I was at work already.
I came back to it in the afternoon and got dash lights a couple times, checked all of the fuses, and they were good, battery connection good and any other connections I could find and check. Fiddled around with a few things, turned the key to the spot just before starting and the check engine light was on, so I thought I was getting somewhere.
Then there was this weird buzzing noise from in behind the glovebox, only when the key was completely off. Pulled the BATT1 fuse (Power ACC/Stoplamp Circuits) and the noise would stop, it seemed like it was trying to blow the fuse.
So we removed the cover below the glove box, and the noise seemed to be coming from some black box. We figure it must be the computer because absolutely none of the electronics are working.
So I unhooked the battery mostly because of the weird buzzing noise that was occurring when the key was out, and I figured if it kept up that it might just catch fire(which at this point may be a good thing, it is insured lol and I have other cars to drive)
So if anyone has experienced the same thing, OR fixed a car with similar issues, OR knows what the heck that black box is, OR knows where the computer itself is located(not the diagnostic plug in I found that) I would really love some help! Once I've fixed this there isn't much left to go wrong...

Thank you all in advance! (and sorry for the very long explanation)

. Remove and fully charge/replace the battery. I suspect the battery died in the summer heat. Frequently, when batteries are deeply discharged, relays (e.g. your "black box") will "chatter" or "buzz." AutoZone will test and charge batteries for free.

. Check all under hood and under dash fuses with a test light or multi-meter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post252145

It's the professional and proper way to test for power through the fuse. Based on what you've said and done, I don't suspect the ECM is bad.

Please buy yourself a service manual by haynes or clymer-they explain every area-u can also go to library sec 629 -do it

I have a haynes manual, I just suck at finding what I need to find in it, but I'm getting somewhere now. I got it running and got it hope with a jump. When I got it home, I tried(while running) the horn, wipers, interior lights, headlights and then it died when I turned the headlights on. So the battery is currently being charged and I'll fiddle around some more with it. Would still like to know what the black box behind the glovebox is, if anyone knows, I couldn't find it in the haynes manual... yet and I'm suspision of the noise it was making before... bustin out the test light tomorrow I guess! Thank you for the speedy answers yesterday!

Thanks for the update. You shared with us what I thought we would hear; i.e. bad battery. I think that is the extent of your real problem.