[SBMN39]

Hey guys. Got into my 94 earlier to go somewhere, just came off a two month project of replacing the timing belt and a three month rebuild of the entire brake system, and putting new tires on it for winter. Gotta love electrical failures for flavor.

So, here's what I know so far. It's NOT the battery, when I was able to get the engine to turn over and start, it turns over nice and fast.

When I first got into the car, the dash lights were very faint when I turned the key.
If you tried to turn the headlights on, you could hear a relay in the dash making racket.
If you tried to turn one of the map lights on (key in the ignition or out), it was very faint as if the battery was dead.

Randomly, the ignition would come all the way on, you could hear the fuel pump engage, and the car would start, but it died at first, as if someone had cut the electricity to the coil.

Eventually the engine would stay running, but once I turned the engine off I was back to square one, faint lights, little electrical signal from anything, and the ignition just seemed to engage correctly at will.

Obviously some sort of resistance or short (I can't tell which) is occuring between the ignition and the battery, and it's doing it with the ignition engaged or completely disconnected with the key out. I've tried messing around with the instrument cluster on top of the dash (headlights, etc, that piece has been loose since I bought the car), as well as the wiring underneath the dash, nothing I'm doing determines when the ignition correctly engages and the dash lights turn on so you can start the car. As of the last time I shut the engine off, I couldn't get the dash to come back at all, just extremely faint lights.

Or something worse is happening.

Does this sound like a rubbed wire somewhere, or does this sound like maybe the computer could be failing, or a short in a wire, or the ignition switch itself? I really need this car running asap.

Thanks, and here's a video kind of illustrating the symptoms.

https://www.youtube.com/watch?v=YuVznPs0_ts

 

[Bob Lincoln]

I would check three major ground connections: from battery to engine block, from battery to left fenderwell, and braided ground strap from passenger firewall to intake manifold. Also check all of the wiring connections at the alternator.

 

[valiant67]

I'd bet on corrosion somewhere at a connection. It isn't a rubbed wire, that would blow a fuse or fusible link.

 

[John Wood]

I agree and sometimes the battery ground cable on the battery post connector (if it is the crimped type) can go intermittant. Sometimes it will make up (connect) with a heavy current draw but have a high restance under light load. with the lights on dim, feel for any heat on the clamp or just make a temporary jumper from a good known ground to the batterry negative post. You might be able to touch the top of the battery post with the lights on and observe for an increase in brightness. Another clue would be any white residue around the crimped connection. Also a voltmeter test between the engine block and the battery negative terminal should show zero with a good ground cable.

 

[SBMN39]

I agree and sometimes the battery ground cable on the battery post connector (if it is the crimped type) can go intermittant. Sometimes it will make up (connect) with a heavy current draw but have a high restance under light load. with the lights on dim, feel for any heat on the clamp or just make a temporary jumper from a good known ground to the batterry negative post. You might be able to touch the top of the battery post with the lights on and observe for an increase in brightness. Another clue would be any white residue around the crimped connection. Also a voltmeter test between the engine block and the battery negative terminal should show zero with a good ground cable.

John, Bob, I understand what you're saying and am going to check ALL these things, but I did want to throw in there...what about the engine shutting off as if the ignition power was cut to the coil? It only did it two or three times, but it tells me that whatever is causing the current shortage involves everything, and the engine coil itself is involved in the lack of current, and were it the battery, it would seem logical that the car would continue to run with just the alternator wouldn't it? (assuming the alternator is working correctly). EVERYTHING is involved in this odd power drain/cutoff.

I need to get the factory manual for this car, been meaning to do it for months, just been investing a lot of money in repairs.

Sun rises early today, out into the 20 degree weather I go shortly to do some electrical checks (I should be grateful I at least have a covered garage).

 

[george w]

There is no braided ground strap between the firewall and engine on the 94 LeBaron with the 3.0. The first thing to check is the heavy ground wire between the negative battery terminal and the engine block. It's right up top there so it's easy to check. Next remove the large, black, corrugated air hose connecting the engine computer to the air cleaner housing. DIrectly below this hose and behind the battery are two plastic, in line, harness disconnects for the negative and positive battery cables. One is white and the other is black. with the battery disconnected pull these apart and make sure the connectors are clean. These are most likely very dirty and covered with grease and such. Next carefully check the several smaller gauge black ground wires leading from the negative battery cable connector at the battery terminal. These are known to corrode and break free from the terminal causing all sorts of odd electrical behavior. Make sure each wire is secure to the battery clamp and hasn't rotted away or broken free. Follow these leads back and make sure that those that ground to the body at the inner fender are clean and secure. Follow back the wires on the positive battery connector in the same way.

I'm almost positive that your problems are in this immediate area, especially those black body ground wires at the negative battery post terminal clamp.

 

[John Wood]

John, Bob, I understand what you're saying and am going to check ALL these things, but I did want to throw in there...what about the engine shutting off as if the ignition power was cut to the coil? It only did it two or three times, but it tells me that whatever is causing the current shortage involves everything, and the engine coil itself is involved in the lack of current, and were it the battery, it would seem logical that the car would continue to run with just the alternator wouldn't it? (assuming the alternator is working correctly). EVERYTHING is involved in this odd power drain/cutoff.

I need to get the factory manual for this car, been meaning to do it for months, just been investing a lot of money in repairs.

Sun rises early today, out into the 20 degree weather I go shortly to do some electrical checks (I should be grateful I at least have a covered garage).

If you have a bad ground wire (i.e. intermittantly becoming high resistance) even the alternator can't run the vehicle. The computer must have a return to ground and receive roughly 12 volts. If the ASD relay drops open for a moment, the engine shuts down.

 

[SBMN39]

If you have a bad ground wire (i.e. intermittantly becoming high resistance) even the alternator can't run the vehicle. The computer must have a return to ground and receive roughly 12 volts. If the ASD relay drops open for a moment, the engine shuts down.

I think I found it. george w hit the nail on the head...

I'm not sure what this connector goes to, but...

The one with the small red clip on the bottom of it. Full of recently spilled brake fluid. Cleaned it out a bit, the car started. Died on me again, cleaned it out some more with a bunch of q tips, it started again. Will let it sit cold overnight and see if it starts in the morning.

 

[John Wood]

You might want to buy an aerosal can of contact cleaner and spray all those connectors. Disconnect, spray, disconnect, spray, (a few times) to sweep the contacts clean of any foreign matter or corrosion.

 

[george w]

This small connector is not your problem. I beleive it's the connection for the cruise control servo beneath the battery tray. Make sure that the heavy black ground cable going between the battery and the engine is tight on the engine end. I suspect your issue is in the ground wiring at or near the battery.
Check those heavy black and white in line snap connectors on the positive and negative battery cables in this same general area behind the battery. Snap these open by pulling them apart ( with the battery disconnected ) and make sure the internal contacts are clean and in good condition.
Next check the various small black ground wires leading away from but attached to the negative battery terminal clamp. Follow these and make sure they're secure where they attach to the body grounds. If you have one of those "bolt on" generic replacement battery clamps then make especially sure that ALL the black secondary ground wires are secure in the clamp. If these become corrupted you will have all sorts of really odd electrical gremlins throughout the car.
It wouldn't hurt to do the same and carefully check the positive side cable and clamp as well.

P.S.

Just watched & listened to your YouTube video. Now I'm convinced it's a ground problem. A really bad battery could cause a similar problem but a bad battery wouldn't turn the starter over. As far as that odd humming sound, is the heater fan switch all the way off ? How about the radio. Is it off too ? A bad or missing ground can cause all sorts of strange back feeds though the electrical system as the current tries to find a path back to complete the circuit.

 

[SBMN39]

This small connector is not your problem. I beleive it's the connection for the cruise control servo beneath the battery tray. Make sure that the heavy black ground cable going between the battery and the engine is tight on the engine end. I suspect your issue is in the ground wiring at or near the battery.
Check those heavy black and white in line snap connectors on the positive and negative battery cables in this same general area behind the battery. Snap these open by pulling them apart ( with the battery disconnected ) and make sure the internal contacts are clean and in good condition.
Next check the various small black ground wires leading away from but attached to the negative battery terminal clamp. Follow these and make sure they're secure where they attach to the body grounds. If you have one of those "bolt on" generic replacement battery clamps then make especially sure that ALL the black secondary ground wires are secure in the clamp. If these become corrupted you will have all sorts of really odd electrical gremlins throughout the car.
It wouldn't hurt to do the same and carefully check the positive side cable and clamp as well.

P.S.

Just watched & listened to your YouTube video. Now I'm convinced it's a ground problem. A really bad battery could cause a similar problem but a bad battery wouldn't turn the starter over. As far as that odd humming sound, is the heater fan switch all the way off ? How about the radio. Is it off too ? A bad or missing ground can cause all sorts of strange back feeds though the electrical system as the current tries to find a path back to complete the circuit.

The humming sound was coming from the headlight switch array, which was turned on at the time the short was occuring, I just didn't *realize* it at the time.

I forgot to mention to everyone, I also pulled the negative battery cable from the motor and used a metal brush to clean those areas, as well as pulled the double black ground wires from the driver's side fender well to clean those with a wire brush as well.

 

[george w]

The humming coming from the headlight switch was probably originating from the solid state dimmer circuitry for the dash lighting. If you don't find anything amiss with the battery cable grounds then I'll look into my 94 shop manual to see if there are any fuseable links or other underhood connectors you should check,
There are some grouding points inside the car for the interior circuits. These are located on the left and rigt side door pillar post areas right above the end corners of the dash You may have to remove the combination door sill/kick panel plastic trim and possibly even the lower dash cover on the left side and glovebox on the right side in order to see or get to these. You'll see several black ground wires/ lugs attached together screwed to the A pillar posts.

If you have no luck with the battery terminal wiring and the grounds check, then just for grins, you may want to try a "loaner" battery or at least have your battery load checked at your local parts store. I've seen these newer "low maintainence" batteries become intermittent or fail very suddenly, as if having a heart attack. The car starts and runs fine, you shut it off and go to restart and then "nothing". Battery sudden death syndrome. I've had this happen personally on several cars over the last few years and it's happened with batteries in some of our company vehicles as well. So much so that I'm getting used to it becoming "normal".

 

[David Eidell]

A volt drop test connecting the battery's negative lead post to vehicle BODY at the cowl would reveal much missing clues. Check volt drop with no load "0" just to be sure, then with headlights, then ignition on, then when cranking. This is hard to diagnose using merely divining rod guesswork.