[jontz]

I have a 96 Deville with a turn signal problem. When I turn on either turn signal, the side light comes on, but neither the front nor the rear come on at all. I can hear a relay click once somewhere in the dash when I turn on either turn signal, but that is it. Could it just be a bad flash module? Any ideas? Thanks!

 

[jontz]

Update: The hazard lights work, so the wiring to the turn signals and the lamps in them are all good.

 

[ewill3rd]

Sounds like a bad turn signal flasher.
They are sometimes buried pretty good under the dash in the driver's area.
Should be a metal can type.
If you can find both of them, swap the hazard with the turn signal flasher to check it.
There is one for each.
(hazard and turn)

 

[jontz]

Thanks! I"ll check it out.

 

[ogbuehi]

Is this the same thing that makes the turn signal blink fast?

 

[peteski]

Possibly. But usually fast blinking is caused by a burned out bulb or wrong bulb.

Peteski

 

[ogbuehi]

I thought that it was a bad bulb also so I replaced them. No dice. It's pretty strange because occasionally they'll blink normal and then start blinking fast. They blink really fast when the headlights are on and only blink slightly faster when the headlights are off. Thought it may have been something with weird but then I saw another caddy (same year and model) with the same symptoms. The top two rear tail lights alternate from light to dark instead of changing brightness at the same time. I'm wondering how hard it is to get to this turn flasher and is there something out there that tells you how to get to it.

 

[ewill3rd]

If your description is accurate you need to change gears, it sounds like you have a bad socket or two, possibly a bad ground.
That will be harder to find on your own.

Typically when the lighting behavior changes with the parking lights on that means a poor ground. This can be due to a fault in a light socket or at the ground location for the lighting system itself.
Do you know anyone who does good electrical work at a local shop?
Even an independent ought to be able to trace down this bad ground if they have a good electrical tech.

 

[ogbuehi]

Well it just so happens that I have a fairly good knowledge of elecricity, I just have no idea where the wires for the lighting system are. I suspected that maybe one of the hots maybe grounding out, but I was hoping that somebody had this problem was able to point out exactly where. I've had to fix other electrical problems in this car and I wound up having to pull the whole dash and steering wheel to find the cause. I'm hoping I don't have to do that again.

 

[ewill3rd]

Start by turning the lights on, then the turn signals, check from side to side and see where a "dim" bulb is compared to the others or the other side.
Then go from there.

If the "hot" wire gets shorted... it usually blows a fuse.
I suspect you have a dirty or faulty ground.
It is doubtful that it is in the dash at all.... sorry I can't point you to it better than that.

 

[ogbuehi]

Thanks alot. I appreciate all of the tips. I guess I'm in for some tough work. There's three lights in the rear tail light assembly. The top 2 are the ones that are supposed blink from dim to bright in sync. Instead the top 2 alternate from bright to dim out of sync. I'll try and see how far I'll have to go to follow the wires before I have to start taking out stuff.

 

[ewill3rd]

It really sounds to me like bad sockets.

If you have the lights on when you take the tail lights out (be careful the bulbs get hot fast) I'd be willing to bet when you move the sockets around they will start working. Sounds like a classic faulty ground contact inside the sockets.

 

[ogbuehi]

I know it's been awhile but I've been busy with work. Well I tried checking all the sockets. No dice. I ordered the service manual to find the location of all the grounds. The one up front in the engine compartment is fine. I'm willing to bet that that there's nothing wrong with the one in the back. I think that some wires from the turn signal and brake are touching somewhere along the circuit. Once I get the proper tools to check the ground in the trunk I'm thinking that's all I can really do without ripping the car apart.