Last post on Nov 30, 2013 at 8:19 AM
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Pontiac Bonneville, Electrical, Sedan
#194 of 203 Quite a few electrical issues in 1997 Bonneville
Jun 06, 2013 (12:14 am)
I have a 1997 Pontiac Bonneville Anniversary Edition that sat up for about seven months. I'm a fix-it girl, so I decided to see if I could get it going. I got it to running easily by working on the battery, adding water, cleaning the terminals, and installing new posts.
The car has had a few electrical issues over the past five years. I think a seal around a door is bad, because the car stays damp inside, sometimes with water on floorboard that i have had to shopvac out (not heater hose--checked and is good). I imagine that the moisture is causing part of my problem. I'll list the problems below:
1) Headlights stay on even after car turned off, key removed, and will stay on until the battery dies. Not as in the twilight sentinel way, but as in they stay on until the battery is dead.
2) Radio/CD Player has issues of flipping around, changing stations, being unable to control from either the actual unit or the steering wheel controls.
3) Dash Panel was working as recently as yesterday. Now the speedometer and rpm gauges are messed up.
Even though the problems above exist (and drive me crazy--I have to unbolt the posts to the battery every day I go to work, grocery, anywhere, to preserve battery), the electric seats still work. The power windows work. The electric antenna works.
I'd appreciate any advice... if you don't mind, when you mention a place to look, be pretty specific, because I don't know everything by professional name.
Thank you so much--jill
#195 of 203 Re: Quite a few electrical issues in 1997 Bonneville [jillchil]
Jun 08, 2013 (3:09 pm)
The radio problem could be a result of corrosion on the ground busses on each side of front seat floor under carpet edge when you take off doorsill. It's about even with the front of the seat. The buss bar is wrapped in electrical tape.
Or it could just be the radio going bad.
The water problem may be the watershield plastic layer on the door over the metal. It's glued to the metal with a black mastic that looses its stickum. The shape of the mastic stripe is to lead water into the drains to feed bad toward the outside of the door. This is all under the inner part with the upholstery on it. The water comes in around the glass and drips down and is supposed to be kept away from the inside by the plastic layer. If not, you may find water tracks below the rubber seal to the inside of the door after rains that hit on that door when the car is outside.
The water may be from sunroof drains: got a sunroof? On the newer body in 2000+, they could break where they went through the floor and leak water inside.
I have also read about some few folks finding their intake for the HVAC that's under the plastic cowl with the slots in it when the hood is raised is no longer sealed. So rain water finds its way inside around the heater air intake opening.
The headlamps, well that's what I've been tryng to find my 98 service manual to look up. They may have retained power on your cars. Does it have the feature where inside lights, radio, headlamps, get turned off after about 12 minutes if you leave them on? That stays on until a door is opened or it runs out of time.
I believe that's controlled by a body control computer. I don't know where it's located, yet, til I find my 98 FSM to look it up.
And you may have a bad headlight switch with the twilight sentinel. I'm trying to think how that would bypass the retained power limit of 10 minutes because you say yours stay on permanently. I would think the retained power would turn the headlights and everything else off at that 10-12 minute mark.
And your two gauges now don't work. The Pontiacs had trouble with corrosion on the contacts where the gauge cluster slides into the contacts. And that may be from your water.
But the thing in the back of my mind is that the battery may not be up to snuff. Low battery voltage will cause some computers not to operate right. So I'd have the battery checked. The running down may have damaged a cell or just age may have damaged it along with sitting.
So I'd start with a known good battery. If there's one you can substitute for troubleshooting purposes that would be good for your efforts.
Other thoughts on leaks are that some Bonneville owners find water leaks on the trunk lid around the air dam if equipped and around the taillights. One even found a leak through the wheelwell housing inside the trunk due to corrosion and the tire slinging water while driving. He used aluminum metal to rivet in place and then sealed her up. But the point is check your trunk.
#196 of 203 Re: Quite a few electrical issues in 1997 Bonneville [imidazol97]
Jun 08, 2013 (6:56 pm)
You've given me a lot of good places to start. I'm getting on tis tomorrow and will let you know the results...
ETA: Will start with battery check with good battery.
Then will replace light switch.
Then will check out module under driverside carpet.
Then will pull radio to see if it's a corrosion problem.
I can do this!
Getting her ready to sale, so these are issues I want repaired so that the next owner doesn't have to fight it.
Thanks again, imidazol97
#197 of 203 Re: Quite a few electrical issues in 1997 Bonneville [jillchil]
Jun 09, 2013 (4:40 am)
The light switch needs to be checked electrically before replacing. You may be wasting money if you don't. The problem is it's in a circuit that complicated by having a body control module that may be bad--or may be reacting to low battery voltage or a bad ground.
The buss bars:
I'm still looking for my 98 manual with circuits on the headlights that may help. Or at least to find out where the body control module is.
I still recommend cleaning your battery connections for ground and positive, especially between the positive cables themselves. Clean grounds where small black wires go to the front fender from the battery connection.
And making sure you have a good battery in the power spot.
#198 of 203 Re: Quite a few electrical issues in 1997 Bonneville [imidazol97]
Jun 09, 2013 (2:01 pm)
Again, THANKS, especially for the photo. Will post results as soon as I figure this out; your advice has been priceless!
#199 of 203 Re: Quite a few electrical issues in 1997 Bonneville [jillchil]
Jun 10, 2013 (4:52 am)
Which headlights stay on? Brights? DRLs--dim brights? Low beam?
There are several parts to the headlight circuit. AND lots of pages of troubleshooting. It really needs to have a Tech II type device that can track what's turned on and off. There's a headlight switch. There's a headlight relay if your can has a certain option, which may be twilight sentinal. Thre's a MALL which is the control module.
One thing I'd suggest is see which lights are on.
See if it does it the same day or night (put a black cover over the sensor on top of the dash for the sunlight so it thinks it's night).
If you pull the dash pieces off to remove the headlight switch, disconnect the headlight switch and see if the headlights stay on under the control of another of these relays and small computers.
Did you check grounds? Loosen, clean, retighten?
Did you substitute a good battery to be sure you've got adequate voltage?
#200 of 203 Re: Traction Control problems [imidazol97]
Oct 22, 2013 (11:11 am)
I have a 1992 Pontiac Bonnivlle and it acts like it wants to start and does not start, I also put in a new coil and i had the modulator tested and it was fine we put the part in and still no spark can you tell me what the problem may be?
#202 of 203 Re: 94 Bonneville won't start [imidazol97]
Oct 22, 2013 (11:32 am)
hi i am having electrical problems my car tried to turn over and there is no spark. any suggestions?
#203 of 203 Re: Quite a few electrical issues in 1997 Bonneville [imidazol97]
Nov 30, 2013 (8:19 am)
I have a 97 Bonneville and have been having the same problem others have had with the car stalling when turning on the rear defroster. I have cleaned the comb splice that is pictured on post #197 and also on #43. I started the car and the wires and the metal comb stay cool until I push the rear defrost button. Immediately the big wire in position A heats up and gets extremely hot. I did not leave it on long enough to stall the car. When I turn off the rear defrost the wire instantly cools back down.
Does anyone have a wiring diagram that shows what wires are running to this comb splice or does anyone have an idea of what is causing the wire to heat up. I have a feeling it has something to do with the ignition switch... with the battery connected and the key in the ignition the door chime sounded. When I unplugged the wire in Position a the chime quit. Any ideas...?