1994 Bonneville Electrical Problems( ROUND 2)

Well I thought I had this licked but I guess not. In my other thread I mentioned I replaced the Alternator and have a new Battery but the car still stalls out.

This morning it turned over with no problems but when I pushed the Rear De-Fog button the car stalled. I turned the key off, turned it over, started no problem but when I tried the power window the car stalled once again.

Now for the third time I turned it over with no problem and it decided to run fine with all the power functions working. I drove to work with no problems and returned home later in the day with again no problems stalling etc.

Shaking my head at this one, I love the car but cannot count on it everyday running for me properly....not liking this at all!!

Any help again would be greatly appreciated!!
Cheers,
FatPat3

Pat, I thought you were all set. This is a tough one. It really sounds as if the bottom drops out so to speak in your electrical system whenever you operate an accessory. In this case you mentioned the rear window defogger (large electrical load), and a power window ( another significant electrical load, but not as severe as the defogger). If electrical system voltage drops to low I mean things drop out for example: ECM, ignition relays, injectors etc, etc, This is what causes the engine stall, major loss of electrical. If you don't operate any accessories, does engine run fine? With car turned off, get a static measurement ( with a multimeter set on volts DC 50 volt scale ) of the battery voltage directly at batt terminals. Then start car, take another voltage reading. Then operate that defogger while monitoring batt voltage, it should drop voltage momentarily, then come right back up to running voltage (alternator should boost that voltage back up) With car running at idle, battery voltage should be up around 13.5 to 14.0 volts.

Mark hello there,

Man your not kidding about the bottom dropping out, I'm scratching my head at this one too. I will take your advice and do that test as soon as I can, some of the guys where I work might have a decent mutlimeter I could use.

And yes it runs fine when I don't use any accessories, so this is what I figured, I must have a major short somewhere like a grounded something hitting and missing now and then. Other than that I'm stumped!!

I'll let you know what happens when I do the tests you mentioned....

Again I thank ya' Mark for the tips!!
Cheers,
FatPat3

Hey FatPat3,

Well just to let you know -I have the same problem - I have cleaned everything very well and also have a relatively new alternator and battery. Have you cleaned off the power bar to the relays? I did, although it made no difference. I am going to start replacing common relays and start looking for chaffed wires. Good luck! -Let me know if you find anything - I will let you know also.

cscottyr

Well I'm back again , and hopefully this is it for the problem LOL. This may sound strange but I disconnected the rear de-fog button(has only 4 wires to it)and low and behold the car does not stall no-more.

The power windows work fine, head lamps are strong, interior lights stay on and so on, car starts right up first shot and continues to do so.

Been driving to work and back and some other small trips around, going on 6 days now with no stalls. Hopefully this was the culprit, one of those 4 wires faulty somewhere causing the grounding thing.

If anything else happens I'll let you guys know but like I mentioned hopefully this is it LOL.

Cheers,
FatPat3

Thats good news FatPat3

cscottyr

hey FatPat3,

Where was that connector located? I think I'll try it.

cscottyr

cscottyr,
I own a 94' and the de-fog is part of the climate control center, you take the panel off your dash, just snaps off,and there are 4 torx screws to remove the control center. There you'll see where the de-fog is connected to the switch, I just unplugged the 4 wires, covered them with electrical tape and the 4 prongs that are from the switch.

I'm hoping this was the culprit, the car continues to run good since then. I don't know if this will help your problems though, I guess it's worth a shot.

LMK how ya make out though,
Cheers,
FatPat3

Thanks FatPat3

csottyr

Hey fatpat3,

Well - I am continuing to look at this problem. I unhooked the defogg - and I could still make it stall by operating an accessory. (Close both windows - then try and close them both some more) I have started to look at individual ckts to see if I could find a chaffed wire or faulty part.
- If you watch your battery voltage when you try and close both windows at the same time it will start to drop and eventually go below 9vdc (within a second or 2). Thats when everything else falls out.
- I am wandering if your new alternator battery combo didn't really fix your problem. When you first installed those items - did the battery have a full charge? When you run a power accessory - both the alt and bat work together to make up for the energy use. If one of those items is not up to speed - your system can drop out. If your new battery was not completely charged - the alternator may not have had enough current to supply it and make up for the extra load. Eventually the battery is fully charged - so when you now use an accessory - the two items working together can maintain enough voltage to now make up for the extra energy drain. Also keep in mind that as these cars age - the resistance in the electrical connections will grow. This will force your alternator and battery to work harder to make up for the loss they feel across these connections. I believe that the alternator GM uses for this car is barely sufficient to handle all of the loads it sees even new - much less as the car gets older.
- I said all of that to say this - eventually winter will be here and you will once again want to use your defogger. You may want to try hooking it back up to see if the problem still exists. With a completely charged battery - it may now work.
cscottyr
- please disregard if the battery was fully charged prior to installation - most arent!

PS- I am considering looking for a higher current alternator and heavy duty battery for my car!

Had a very similar problem. Turned out the main accessory power cable (pigtail?) that runs to the battery terminal had become frayed at the clamp and was arcing. What a nightmare!

thanks romangal for the post - I haven't had any time to look at it lately - though I might go out and inspect that pigtail closely - thanks for the post!

cscottyr

I am having the same problem, relatively speaking. My wife's 96 Bonneville has been stalling lately. It all began with problems starting (fuel pump not turning on). I noticed that when it wouldn't start, the windows and door locks wouldn't work either. I started driving the car to see if i could duplicate the problem. Well, last friday on my way to work I tried to roll down the drivers side window and the car quit. I coasted to a stop, called my wife to have her drive me into work, and figured I'd worry about it later. After work I fought with it. After a 45 minute battle it started (as near as I can figure holding down the power window switch did it) so I drove it home. When I got home, as a test I tried to roll down the driver side window again. Once again it stalled. I have read what has been written about the alternator and battery, but don't believe that is my problem. The guage is reading the high side of normal (acceptable) and the battery is good. But the symptoms are identical to the ones you have been listing. I looked at the "pigtail" and all appears to be fine. To test this I ran another wire (just in case the wire was bad) and still had no luck. My care has not been able to start since I got it home, no matter what I try, and I am completely at a loss. My wife and I both love the car and don't want to get rid of it. Does anyone have any other suggestions?

This sounds a lot like what's happening to my '94.

Here: http://www.automotiveforums.com/vbulletin/showthread.php?t=735752