electrical problem

powerinit · #1 08-08-2006, 06:49 PM

I have an 86' Brougham and when ever you use the left rear window switch (the switch on the main set for the driver's use) ALL electric cuts out on the car. We just checked it again after cleaning the battery post. We started the car and moved the switch and the car quit along with everything else, same with the car off. What could be wrong? Thanks for any help.

powerinit · #2 08-15-2006, 07:54 PM

anyone have any ideas? it's gotten worse lately. The other night my dad tried taking it to work and as soon as he turned the headlights on, the car instantly died. He tried it 3-4 times with the same results, so he just took our truck. I went out later and no lights worked (interior or exterior), then out of no where, everything turned on and worked fine. This afternoon we tried it again and everything cut out like before, but never turned back on. The window switch works fine now which is weird because now nothing else is. Right now we are just gonna buy a new battery and terminal screws (negative was shot and battery not the greatest). Anyone have any ideas? Thanks

P.S. My chevy beretta does the same thing.

silicon212 · #3 08-15-2006, 08:13 PM

Quote:

Originally Posted by powerinit

anyone have any ideas? it's gotten worse lately. The other night my dad tried taking it to work and as soon as he turned the headlights on, the car instantly died. He tried it 3-4 times with the same results, so he just took our truck. I went out later and no lights worked (interior or exterior), then out of no where, everything turned on and worked fine. This afternoon we tried it again and everything cut out like before, but never turned back on. The window switch works fine now which is weird because now nothing else is. Right now we are just gonna buy a new battery and terminal screws (negative was shot and battery not the greatest). Anyone have any ideas? Thanks

P.S. My chevy beretta does the same thing.

Well hell, I would suspect either grounds or a fusible link somewhere. I don't really know where to start aside from suggesting that you pore over your electrical system with a fine-tooth comb. One possibility might be where the wiring harness passes through the firewall into the car - there is one bolt (7-mm) that attaches this (it's on the firewall underneath and behind the windshield washer fluid tank) to the fuse block on the other side of the firewall. If this bolt comes loose, lots of weird stuff can happen - including the problems you are encountering.

powerinit · #4 08-18-2006, 12:17 PM

Thanks for the reply. I thought it was bad ground off the battery first because the negative hookup was shot and pretty damn loose. We got the new battery and new screws and I tighened them up good, but some problem, so I ruled that out. i'll have to check that bolt out today. Would the bolt be on top of the harness or under it? Thanks again

HLandin · #5 08-18-2006, 03:48 PM

Loose connections are BAD. Now, you don't need to make them super tight, especially on something soft with lead (like battery terminals), but being tight assures a good electrical connection. If they are loose, they can cause an intermittent failure or things to not work. This is because a loose electrical connection cause high or very high resistance. This resistance is just like adding a resistor in series with the device. Now, electricans will know that loads (anything with resistance, inductance, or capacitance is a load) in series will cause a voltage drop over each load proportional to the resistance (higher resistance, higher voltage drop). If the loose connection has high enough resistance, you will not have enough of a voltage drop over the load to make it work because total voltage drops in a circuit must equal the voltage applied (12+ volts from battery/alternator). Hense, the devices in your car are designed to work with 12 volts applied minus a very slight voltage drop through the wiring (remember, anything with resistance will cause a voltage drop). If you have a good electrical connection (less than 1 ohm), the drop will be almost no-existant (a couple thousands of a volt or 1/1000 volt).

PeteA216 · #6 08-19-2006, 12:33 AM

What about the small ground wire that branches off the main ground wire and connects to the body. All the power died in the parts wagon I bought a year ago while I was trying to drive it home, and all I did was loosen and retighten the bolt and it was fine.

powerinit · #7 08-19-2006, 01:56 PM

seems pretty easy to try so ill check it out today when I get some time, thanks

HLandin · #8 08-22-2006, 05:45 PM

By loosening and retightening the bolt, you probably removed some oxidation on your connection. Oxidation is a poor conductor (because it is not pure metal anymore) and that is why it is offen recommended to clean a rusty ground. That extra resistance caused by the oxidation is the same as having a loose connection. Remember, the higher the resistance, the higher the voltage drop (and you connection is not where you want your voltage drop to be, you want to apply as much voltage on the load as possible).

powerinit · #9 08-23-2006, 08:56 PM

well, I got a new battery, new terminal bolts, redid that ground wire, cleaned the power wire on the starter (the one that comes from the battery) and now luck. Today I took the harness off from the light switch itself and it didn't have any power there (with and without the ignition on). So I ran a wire from a power source to that harness where the headlight wire is and they turned on. I also ran a wire from a power source to the power wire on the harness and then the interior lights come on like they are supposed to do, but if you unhook the power (they stay on themselves after this) source from it and shut the door, next time you open it, everythings off again. Think the headlight switch could be going bad? or still a wiring problem? Thanks

bobss396 · #10 08-24-2006, 08:03 AM

Since your power windows and headlights are relatively big load draws on the system, I agree with the others that there is a bad connection or dead short somewhere. Go over the under-dash fuseblock really well. Pull the biggest main fuses first and see if they are loose, cracked up the middle or partially blown. Then go to the smaller ones as well.

Your local library might have a body/chassis manual for your car which will show you where all the fusible links are, you should also be able to trace the headlight and power window circuits to see where they are common.

Do you have a good auto-electrical shop close by? They could probably fix it really quickly rather than going through the trial and error method.

Bob

powerinit · #11 08-24-2006, 10:37 AM

The thing that I think is weird is, one night I took out the window switches, but didn't do anything to them, just pulled em out and they now work good as new. I think it's a short like you guys say. We had a cousin (a mechanic) look it over, he checked the fuses/ block and it all checked out that I know of. He said he's gonna call his uncle who works at a shop/ dealer, so if that doesn't work, i'll take your advice and have a shop look it over. Thanks for all the help so far guys and hopefully i'll have this caprice back up and running again soon.

silicon212 · #12 08-24-2006, 11:28 AM

Quote:

Originally Posted by powerinit

The thing that I think is weird is, one night I took out the window switches, but didn't do anything to them, just pulled em out and they now work good as new. I think it's a short like you guys say. We had a cousin (a mechanic) look it over, he checked the fuses/ block and it all checked out that I know of. He said he's gonna call his uncle who works at a shop/ dealer, so if that doesn't work, i'll take your advice and have a shop look it over. Thanks for all the help so far guys and hopefully i'll have this caprice back up and running again soon.

Did you ever check that bolt I was talking about? It's in the center of the wiring harness "plug", which plugs into the fusebox on the engine side of the firewall, underneath the W/S washer tank. Most of the car's wiring passes through that block.

Blue Bowtie · #13 08-24-2006, 11:51 AM

FWIW, if it isn't starting a fire, it's not a "short" - It's an "open" circuit. A short is a condition where all power is shunted (like connecting a big jumper cable right across the battery or power source). An open circuit is caused by high resistance or the lack of continuty (as in a poor connection, cut wire, or unplugged connector). A true short will take out a fuse, fusible link, melt wires, or burn your car to the ground, whichever happens first.

powerinit · #14 08-24-2006, 01:51 PM

well sorry about that then, I don't know much at all about electrical, wiring, etc. Would I have to unplug the harness that goes into the box to reach the bolt? or just look under the harness?

silicon212 · #15 08-24-2006, 02:58 PM

Quote:

Originally Posted by silicon212

Did you ever check that bolt I was talking about? It's in the center of the wiring harness "plug"

By this, I mean the bolt is used to hold the plug to the fusebox. This means that if the bolt is loose, there won't be proper connections (many opens) and therefore you'll have trouble.

POST REPLY TO THIS THREAD