I'm going to start off and say I have a pretty strong knowledge behind cars (*cough* Saturns *cough*), so if you feel like you can help, speak as technical as possible.

Here is the problem: My rear brake lights and hazard light (on the trunk) are not functioning. The brake light in the back window works perfect. The turn signals in the rear work perfect as they are a different bulb and circuit. The rear taillights work, but when the brakes are applied, the 2nd filament doesn't light up, and when I put the hazards on, the 2nd filament doesn't light up. The odd part is the hazards in the front work fine.

So, I printed off a 97 - 00 wiring diagram for the brakes/hazards and I'm looking it over. At once time I noticed a small stream of smoke coming from the column. After I mentioned that, my friend told me that the only brake light I had was the rear windows light. I took the column apart and checked the hazard and turn signal switch. Everything seems fine. The hazard switch should be functioning fine since the front hazards works. We also checked the hazard switch for any burnt wires since I did see smoke at one times, but nothing was burnt. We checked the brake switch on the pedal, but that functions fine since I have the rear window brake light. All of the fuses have been checked and continuity is good.

The main convern is that we are not getting power to the wire on the bulb socket that powers the brake/hazard filament in the bulb. The bulbs have been replaced.

The car is a 99 Cavalier, RS OHV if it matters. Has anyone else experienced this problem?

My first thought would be a relay. Since you know the bulbs are good and that the power gets there for the signal light you know it isn't a broken wire.

I would definitely check out a relay.

Well, I pulled off the turn/hazard flasher that's under the column. It looks like a big green relay. I took it apart and it's a circuit board with a coil, resistors, diode, and a IC. I pulled apart the switch for the turn signal and hazard switch and it didn't look like anyting was burnt, nor did it smell like it. I've been searching for a relay box that is seperate from the interior and underhood fuse box, but I can't find anything.

The only conclusion that I'm coming to is that the mechanical hazard switch could be partially ruined.



Maybe the contact points for the rear of the car are faulty. If it was a wire that burnt up, it would have to short out. In that case, a fuse would have been blown. Since I saw smoke coming from the hazard switch area, most likely it's the switch itself.

If you think a switch is bad, jump the switch using a 10 gauge jumper wire. Then try the hazards or brake lights see if they work. If they worked when jumped you know its the switch, if they still dont work, switch is good.

Secondly are all your other lights operating normally and nothing else is wrong?

The two side brake lights are wired on a different circuit than the third one is.

The two brake lights that are out, do you have power, and do you have ground?

As for your hazards thats odd they work in the front and not the back. That would lead me to believe the switch is good. Because if the switch was bad no power would go through it at all. Since you have power going threw it I think its fine.

I'm really thinking you have to much resistance.

I assume you know how to check resistance, what is the resistance of the rear brake light bulbs. Do you see any corrosion built up in the sockets?

Maybe you have excessive resistance. After all one amp will flow through one ohm, but not enough amps and to many ohms it wont work.








- 2004 Cavalier - 124k, owned since new

Use a Computer Safe test light or a Digital Volt Meter to test the wires in the back and see if power is getting back there. If it isn't then the problem is probably in the switch. Check both the front of the socket where the bulb plugs in and the back just incase the problem is in the socket.

There was a post about this same problem about a month ago. Since your back lights are dual filament, it sounds like the second filament has burned out. You might want to change out the bulbs and see if that fixes your problem.



98 Z24

RIP Specks

the thing is that the hazard switch is not the switch that controls the lights. there is way too much current drawn by them to go through a regular switch so they use a relay. one switch can be burnt off in the relay...ie: your back flashers...and not the other...your fronts.
I am an electro mechanical engineering tech...if you could e-mail me your wiring diagram or send me the link where you got it I will look it over as well.
Maybe i will find something you over looked.

BTW that smoke you saw would definitely mean that one of those little switches burnt off... a new relay for that circuit should be fairly cheep...try a junkyard...maybe get one for less than 5 bucks.

When something does that in our systems on my ship we call it "releasing the factory installed smoke".

E-mail is nytemare99@hotmail.com