Yesterday I changed some brake light bulbs on the driver&pass side. Driving back home from my friends house yesterday evening I encounter a wierd problem. When I applied the brake the time display in the radio dimmed and the dash lights started to flicker. When I got the car in the garage I turned on the headlights and they started to flicker also. I figure I may have a loose groundwire some where but don't have a clue which wire is the ground. Everything worked properly until I changed the bulbs yesterday. Took it back over to my friends and he put a voltmeter on the battery. Battery and alt are okay. 13.9volts. This is an intermittent problem. Driving back over to my friends it didn't do it. He said sometimes it the ground wire doesn't make a good metal contact it may cause this problem.
Does anyone know if there are any ground wires on the chassis? Reason I am asking I had my car up on the rack Monday morning to have the front disk brakes replaced and the mechanic had all the wheels off. Just wondering if there are any grounding wires next to the wheelwells on the Bonne? I notice that light socket has three wires going into it, A blue, black, and a brown wire but I don't know which one is the ground. Any help would be appreciated. Thanks.

Check the bulbs carefully to see that you have installed the correct bulbs and that they are not forced into the socket wrong, or not completely in there.

Thanks for replying. I was rootun around (troubleshooting) this morning and I think I found the problem. One of the light sockets on the pass side is inop. The metal tab that goes down the side of the socket had broken off at the top. Maybe that was why I wasn't getting a good ground. I have a spare taillight that came with the wiring harness so I will try and swap out the harness and see if that will help.

Right; that'* your ground connection. Here'* what was happening when things started to go weird on you:

When you stepped on the brake, current reached the brake-lamp filament but dead-ended on the other side, where the (broken) ground connection was supposed to be. Because the taillamp and brake lamp filaments share the same ground point within the bulb, the brake-lamp current was able to double back through the taillamp filament and backfeed through the whole exterior lighting circuit in search of a ground. I suspect your fluorescent displays detected the current flow in the dash backlighting circuit and dimmed themselves, thinking that the outside lights were on (which they were, sort of).

To answer your other question, the black wire at the socket is a ground and the brown wire is your taillamp/parking lamp circuit. The third wire is for the high-intensity filament, such as brake lamps in the back or turn signals in the front; its specific color varies depending on what corner of the car you're looking at, and whether or not the car uses separate circuits for braking and turn signals. (e.g. If not, the left rear brake circuit is yellow and the right rear is green.)

Well, you need to replace the socket with a correct new one, and you'll be all set.

Andy, Thanks for you detailed explanation. Thats what I did last week when this problem started. I had a spare harness so a friend of mine cut the scoket and soldered and spliced it to my origional harness.Acouple of days ago went to the local U-pull-it and I got two extra harnesses with the same connector as mine and replaced my old harness with the new one on the pass side. bonnie94sse came down yesterday to pickup his cluster and he and i went back to the wrecker for a local "tour'. He even found some extra parts for his Cutlass. I got me two more wiring harnesess so now I have four. After replacing the harness on the pass side the problem is still there but not as bad as last week. This morning before I started the car I turned on the parking lamps and they flickered all around for about 10 secs then steady burning lamps. Since I have the extra harness I am going to replace the driver side harness this evening and see if I still get an intermittent flicker. Everything was fine a week ago until I changed the bulbs on the pass side when it all started.
On a side note this past weekend I replaced the bulbs on the drivers side since I had some spares. When I removed one of the 2057 bulbs one half side side of the bulb had a milky white appearance to it and looks to be a small circle which looked like it may have melted. I am beginning to wonder if that might be the culprit? I will see what happens when I replace the harness on the drivers side and will post an update. Thanks again.

I don't totally follow everything you're describing here: was it the bulb or the socket that looked like it had melted? Was the milky-white bulb still working at all?

I would suggest just replacing the bad bulb first, then see if a problem remains before you go cutting out what may be perfectly good wiring. Have fun...

P.*. Once you're sure that all your exterior bulbs are in good shape, if the flickering symptoms persist, you might want to try a new headlight switch. Do you have Twilight Sentinel on that car? If so, do you ever see flickering when the TS relay turns on the lights, or only when you do it manually by pulling out the headlight ****?

Turn on the tail lamps and start pulling out the bulbs one by one until the problem goes away.

acg ssei, Sorry, If I got you a little confused on my explanation. The bad socket with the broken tab was on the pass side. I replaced the existing harness with a new harness and bulbs. Problem still existed with intermittent flutter. The white bulb I discovered a few days which was on the drivers side. Yesterday evening I replaced that harness with a new one and new bulbs. Everything looked to be okay. I had both sets of lights out of the tails to check if I still had the fluttering but could not get the bulbs to flicker. I figured problem solved. This morning before I started the car I put on the parking lamps and the flickering returned but not as bad as before. It lasted just a few seconds then the lamps burned steady. I had one instance while driving around this morning when I applied the brake and I saw the light on the time display flicker for a split second. So far it has not done it again. The one thing that I have not checked is the wiring that is behind the plastic cover on the back of the trunk. I might just remove that cover just to check to see if there are any wires that are frayed or chaffed.
Do you know if there are any grounding wires that are attached near the wheelwells under the chassis? I had the car in for brake service on 8-28-04. I know everything was working properly before I took it in for service. The mechanic had all four wheels off the car. When that was completed I went out of town for a few days and when I got back and replaced the bulbs that is when I started having problems. He replaced the brake shoes on the rear wheels and I am just wondering if there are and grounding wires that are located at or near the wheelwells that may have come loose? Thanks for your assistance.

Hmmm... You might want to try wiggling the headlamp switch **** from side-to-side and see if that provokes the problem. I know you'll probably get flicker from the dash lighting if you _turn_ the ****, since that will turn what is (usually) a dusty or oxidized rheostat, but I'm interesting in the main contacts that turn on the outside lights when you pull out the ****.

Go right ahead, although I doubt you'll find a problem there. Also, you have no brake lights in the trunk lid, and you mentioned seeing some flickering when you step on the brake, so I don't think the lid wiring is going to reveal much. (But stranger things have happened...)

No, ground wires are typically not exposed since they would be vulnerable to road debris or snow packing. There are ABS wheel sensor wires down there, but they wouldn't be involved here. The rear lighting is grounded somewhere inside the trunk, if I remember right. It would be a good idea to find it and make sure it'* screwed down nice and tight.

I hate to say this but I think it'* much more likely that you caused something than he did. I'm thinking you have a loose or intermittent ground problem somewhere, and possibly a bulb that'* not in its socket properly. I would especially check any double-filament bulbs to make sure they're plugged in the right way around. The offset pins on the side of bulbs like the 1157 are supposed to ensure that they will only go in one way, not 180° out of position, but brute force can do amazing things.

Also check your battery cables, especially the ground cables, at both ends.

That was one of the first things I checked when you mentioned the headlight switch. Jiggleing it around did not produce the problem. Don't have the Twilight Sentenial. The wires I was referring to runs along the bottom of the trunk well. I have a big piece of gray plastic that is near the lock assy. I think I will remove that tomorrow and check for chaffing. Just got back from alot of stop and go driving and so far everything is okay. I just wasn't sure about the wires on the bottom of the chassis. Will do some further investigating tomorrow with the wires in the trunk. Thanks again for your help.