Brake Lights Blowing Fuse

[tlong]

Why is everyone yelling at me? No brake lights including the third one.
Replaced blown 20A and it's OK for 10 minutes, then it blows again. Turn signal and tail light function is fine. Pedal switch? If it's a short to ground could it be intermittent? It's parked until this is fixed.

Thanks in advance for suggestions.

 

[Topless]

For starters, check the bulbs and sockets. There might be moisture that is causing the short. The use of electrical grease will cut down on that if it is the problem.

 

[tlong]

Not the switch...put in a new one and the fuse lasted 20 minutes. It's at the dealer service dept. They have tried to find the problem for 2 days.

Brake lights! Stumped the experts so far. I can't believe there is no warning given on this failure. My '80 Datsun had that. 140 sensors but you can drive around with no brake lights? Just a little put out on this short in the electrical system that defies discovery. Off the road until resolved. Any other suggestions?

 

[c4cruiser]

Definately sound like a short somewhere. You may have a wire that has the insulation worn down to the point where the bare wires are touching metal.

What seems to be strange is that the high-mounted lamp goes out too. While both the high mounted light and the brake lamps are controlled by the same switch, there are separate wires to each from the brake light switch. I would suspect something wrong in the harness around the brake light switch or even the harness connector itself.

The fact that the turn signals work (which use the same wires as the brake lights) makes me think that it's the harness connector. If you turn on a turn signal or use the 4-way flasher and let them remain on for a half-hour or so and no fuses pop, I would suspect the harness around the switch or the connector. There is always a possibility that the new switch could be bad, but I would look at the other items.

 

[tlong]

Electrical problems are a challenge. The tail lights work from a different circuit than brake/hazard as you stated. We can't get it to short now at the dealer service. They wiggled all the wires and checked for a break to ground.

There is a capacitor between the two wires at the switch wire harness. I'm going to replace that too. It sucks having that little gremlin rattling around the car. Thanks for your suggestions. They left the hazards on for a while 2 or 3 times. No blow, of course...that's going to happen on the way home.

 

[newbie88]

tlong,

i'm no electrician but had a very similar problem and traced it to worn insulating wires touching. in my case it was caused by a short from the wires contacting the electrical leads out of the stereo deck. was the last place i thought to look. i didn't discover this personllay so can't give you details. all i know is once the deck was pulled, it was fairly apparent where the short was coming from. hope this helps.

nb

 

[tlong]

Thanks newbie. I have a real situation emerging from what was a simple problem. The tech at the dealer-all of 22 years old-couldn't make the fuse trip. On the way home I fired the hazard lights... pop.

Upon replacing the fuse I heard the flasher for the hazards weakly blinking then blow. I think it's the flasher circuit for the hazards. I had never touched them before. It's the wiring or the flasher for that part of the shared circuit (maybe). He suggested replacing the flasher, but didn't know there was a seperate one for hazards on the passenger side...yikes!

I have a different stereo, and it could be behind it. This is a very frustrating glitch. Trying not to get sour on the whole vette thing. It's not the first b.s. GM nightmare over the years.

It's heading to David at Tom Jumper Chevrolet. He is the man. If he can't fix it it's over to Father O'brian for the exorcism.

 

[KOPBET]

Unless I missed it, you don't mention what condition makes the fuse blow. Is it with the brake pedal depressed or not? 10 or 20 minutes doing what?

Not the switch...put in a new one and the fuse lasted 20 minutes.

There is a capacitor between the two wires at the switch wire harness.

Can't be the switch or the capacitor. The switch IS a short and the capacitor is an open to DC. If it shorted all you would do is turn on the brake lights without depressing the switch.

The tail lights work from a different circuit than brake/hazard as you stated.

The circuits are the same from the turn/hazard switch back. And of course the third lamp goes out, it's operated from the same fuse.

You don't mention doing anything with the traction control module (If fuse blows when applying brakes).

 

[tlong]

Thanks Kopbet. From previous posts I know you know about these cars. Wouldn't that trigger a code or light (Service ASR)? The fuse will blow applying the brakes or engaging the hazard button on the column. It took 10 minutes to blow but now it is immediate.

It's in the hands of the vette yoda David at Tom Jumper here in Roswell, Ga. I pulled into the service area and in 15 minutes he'd disassembled the driver and right side panel and the whole rear panel covers. He tried to find an obvious chafed wire to no avail. We proceded to his bay and he whipped out the Helms wiring diagram and concluded that the common leg of the circuit was in the turn signal wiring and had to be shorted, located in the steering column. Houston, we have a problem. He is on it as I type.

Certainly a shocker seeing the interior torn out and laying about the service entrance floor. The saga of the brake lights continues....and I'll certainly post the solution in case it happens to you.

 

[KOPBET]

Steering column sounds logical to me too. Perhaps something broken internal to the turn/hazard switch in the column. Broken switches like that can do some funny things. Whatever it is, it sounds like it might get expensive tracking it down.

Yell back at us when you know more. Good luck.

 

[tlong]

This fellow working on it had the eyes of a gunfighter at high noon. 20 years experience with vettes on my side, and his statement that he hasn't been stumped yet made me feel better. Hundreds of dollars to fix brake lights has me in a bit of shock...and reaching for aluminum attitude enhancement cannisters after work these days. I can fix most anything but this GM wiring was concieved at Woodstock during the Hendrix show undoubtedly sampling the "bad" brown acid.

 

[KOPBET]

So how many cannisters have you gone through now?

 

[tlong]

Consumption of attitude cannisters has come back down to normal which in itself is excessive at times.
This is the next to last problem I'm enduring with this model vette. Going back to '69 if anything else happens I can't fix, assuming this can be fixed without running a wire to the back to operate the damn brake lights. Ridiculous.

 

[KOPBET]

So how long has Mr. Gunfighter been working on it now?

 

[tlong]

Fourth day at this dealer. He found a chafed/exposed wire in the steering column exactly where diagnosed from the schematic. Now all he needs to do is re-assemble the interior. $92 an hour. I'm hoping for pity. His waiting room is full and you have to wait your turn.

I hope this helps fellow members in the future as nothing was covered on this fix. I will stop whining and consider it lucky to be the first big problem in the year since bought. We all know the pain of the word 'dealer'. Now we see how many things got broken fixing this.

 

[KOPBET]

Glad you're all fixed up. Too bad the expense was .

How did he repair the wire? Cover it up with tape?

Do you know which color wire?

 

[tlong]

Going to rescue the hostage today. It was re-insulated. Probably $50 for parts (3 inches of tape) The wire was chafed by a very sharp edge at the bottom of the column where they go up, the hazard circuit which is shared by the brake lights.

I am ashamed to say how much this little episode cost me. Suffice to say I could have flown to Vegas and had a damn good time with change left over. What a joke. I guess it's old news that dealers are an absolute rip-off.

This car is now on double secret probation, and best appreciate it's pampered lifestyle.

 

[tlong]

This has to be told. The dealership saga continues. Yesterday after picking it up we were cruising over to my friend's house, all systems go. Suddenly the steering column and wheel are engulfed in smoke! Enough to barely see out the windshield.

Not having the ejection seat option I had to bring it in. Killed the engine and coasted into a driveway and we bailed. I knew it was going to burn. Well it didn't. It fried the horn circuit, with no other damage. Looked like a a smoke grenade for a minute.

Drove home, and took it back to the place with a fire extinguisher in the passenger seat with the pin pulled. I knew it wouldn't get out of there without collateral damage. Maybe this will be it and I can get back to the fun part again.

 

[KOPBET]

OUCH!!!


So sorry to hear that! Black crusty wires or other melted components should be easy to spot now. :cry

 

[tlong]

It put new meaning to 'Torch Red'