Tail lights on '96 Concourse

[debartz]

I would like to find out if anybody has had problems with the tail lights on a '96 Concourse?

Here is the history of my problem. A few months ago I noticed the left turn signal blinking faster than the right. Thinking it was the blinker, I thought I would replace it in the spring. Well, good plan, not so good results. After a while someone told me that when the left trun signal is on and I step on the brake the top left light would go out. Ok, then about a week later the sound of the turn signal started sounding like a bzzzz before the light came on on the dash. This past weekend I replaced the lower bulbs (there are 3 bulbs in each rear light assembly). It still did the same thing. I then cleaned the posts on the other 2 bulbs on each side. Nope still the same. Just wondering if it sounds like a ground issue?

[Cadillac Jim]

It might help if we have the OBD codes. If you got a warning light or a message on the dash, that means that an OBD code was set and it will tell us what the problem is.

[KHE]

The sockets are known to burn and not make good contact. The solution is to replace the sockets.

[debartz]

No OBD codes or warning lights. Nothing.

I'll check the sockets and see if I can clean them.

[davedog]

I had all kinds of strange issues on my 87 Deville - similar but not exactly. One weekend I started at the tail lights, inspected lights/sockets, and when all looked OK I decided to follow the harness from each light to the front of the car. Well, it didn't take long to find the issue. When I pulled up the trunk liner I discovered that somehow the harness had gotten moved and was pinched under where the jack mounted to. The entire harness was one big black charred melted mess. Even the back of the carpet was burned. I cut that chunk out (about a foot long!), and just patched new pieces of wire in, matching the colors. Problem solved. It even fixed an issue I had where the car liked to stall out in the rain.

I know it's probably not the same issue, but point being - maybe follow the harness and see what you find...

[debartz]

Thanks, I'll check it out. Right now the weather is not great here in the land of cheese. I'll get to them as soon as the snow stops flying. Right now they are not working at all. All I did was clean the old bulb contacts for the top 2 bulbs and replaced the lower 1 on each side. The bulbs are much brighter but still not turn signals. I will keep at it as weather permits.

Thanks again,

[Cadillac Jim]

There is a lesson in davedog's post. A lot of problems that seem inscrutable from the codes (or lack of codes) are solved by walking through the wiring harness and finding unexpected damage. This happened to me once and it turned out that wires to the oxygen sensors were not in their ties and had burned against the exhaust manifold.

[KevinW]

I encountered a similar problem on a 1996 Concours. The upper-left indicator would appear dimmer than the others on an intermittent basis and would occasionally trigger the bulb-out warning, where the flasher unit fires at twice the normal frequency. After dissecting similar vintage sockets, I determined that the problem was likely a point of high resistance between the ground wire terminal and the inner socket bulb contact terminal. The resistance to ground was 1.2 ohms. I decided to perform a quick experiment and simply removed the terminal retainer clip and manipulated the ground terminal in-and-out about 30 times; this scrubbed the internal contact area without having to disassemble the socket. I sprayed an oil-based rust proofing product in the socket to discourage additional moisture intrusion and corrosion. It's been working fine going on 2 years now.

[debartz]

Wow, that sounds like the exact problem I'm having. All 3 bulbs in each tail light work and are on. But now I can't get either side to flash. Really wierd because before I replaced the lower bulbs I at least had a normal right flasher with a left flasher that fired at twice the normal frequency.

[debartz]

One question, I didn't do something wrong if I used bulb grease on the lower bulbs when I installed them, did I?

[debartz]

Sorry to be a bother, you guys have way more experience than I do. I still don't have any turn signals. Could it be that the side rear turn signal light is burned out?

[KevinW]

Dielectric grease shouldn't cause any trouble. It sounds like you need to retrace your steps and focus on things that would affect both left and right circuits, such as fuses and the flasher unit itself. You might try removing each rear bulb, one at a time, and evaluate the functionality after each change.

[PAUL T]

Have you checked the other bulbs on the circuit, such as the front turn signal bulbs? I know I had problems with the sockets on my 94 Concours and could not find any exact replacements.

[debartz]

Well, remember, I live in Wisconsin. I don't have a heated garage so I'm available to the weather. It has been cold, darn cold. Today wind chill is around zero, temp at or near 20. I keep saying it will get warmer but the cold just keeps hanging on. I will get to the bottom of it soon, I hope. I keep driving and not using the turn signals because they don't work at all. All the rear lights work, just no turn signals. I, at first thought it was the blinker module. And I may be right. I will check all the other bulbs to be sure.

Thanks again.

[Logan]

The problem is often bad sockets. They can look ok....but be scorched inside the actual plastic socket. Kind of invisible internal damage.

Not exactly the pic I was looking for (10+ year old pic..). But in the socket on the right you can see some browning of the plastic. It's a bad socket. I don't want to imply that every socket that has some heat/browning is bad. But it can be...and it's really not practical to try to repair. In this case the solution is to splice on a new socket.

The problem can also be the turn signal switch inside the steering column.

[debartz]

Well I did get a chance to do some investigating this weekend. All lights go on when I turn on lights. Brake lights work also. Turn signals lights still don't work in rear only. Front trun signals work, but don't blink, either side. It almost sounds like a bad ground for the rear lights, but then if it was a bad ground why would the lights go on and the brake lights work?

[debartz]

I thought I'd get back to the forum and let you know what I found out. Yah, it's been a long time. I just didn't want to spend the money if it was the turn signal switch in the steering column.

I finally got a quote from one of our local shops and they said $195 to replace the switch in the column. I figured that was a good price and schedlued to get it done. The mechanic asked if he could do some checking first just to be sure and I told him he could. They found that the turn signal module under the dash was bad. Part was $28 and an hour of labor. Bill was just over $110. I'm sure glad I said to do some checking.

[Texas Jim]

Glad you got it fixed and Thank You for reporting back on what caused it.,,,