brake light problem.....someone please help

Green 94 5.0

Founding Member
Mar 25, 2002
2,590
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Ft. Lauderdale, FL
well, i finally sold my yellow 94 gt, but there is one problem that needs to be addressed before the new owner takes it. the fuse for the brake light/hazard lamps keeps blowing. the strange thing is, if the car is sitting still, the fuse wont pop, and if the car is going in reverse, the fuse wont pop. the only time it pops is when the car is moving forward. pretty much the car can sit for an hour with the brake lights on and not have an issue, but the moment the car begins to have forward momentum, the fuse is toast. does anyone have a clue as to what this can be? if my hair was long enough i would be pulling it out right now.
 
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That's definitely an odd one. Not in reverse, but in drive? Maybe it's something with the alternator increasing voltage too high when the engine speed increases? Bear with me on this one, but my logic behind that is... only in drive, but not reverse because the reverse lights eat up a little more voltage. Can I have a prize if I'm right? I'm totally guessing on this one :D
 
StangGT1995 said:
That's definitely an odd one. Not in reverse, but in drive? Maybe it's something with the alternator increasing voltage too high when the engine speed increases? Bear with me on this one, but my logic behind that is... only in drive, but not reverse because the reverse lights eat up a little more voltage. Can I have a prize if I'm right? I'm totally guessing on this one :D
cant be. we unplugged the sensor on the tranny and it still does it.
 
I wonder if it has to do with the brake light on your dash, does that work with parking brake? I mean, will putting the ebrake on pop the fuse as well? I am guessing no.

I think ernan is right with the abs system. Maybe you could remove all 4 abs sensors & tie them to the side and see if it still does it. Then you have isolated the problem to the abs system.

So if I am understanding your problem, you can drive in reverse all the way to redline, and it won't pop?? (i.e. are you getting some speed up when you go in reverse, or just backing up slowly?) What speed will the fuse pop?

If you want to dump the car, you could always put a auto-reset fuse in it's place, and see if it will get the guy down the road.
Scott
 
Cig lighter and the seat are connected to the brake lights. if you seat wire is grounding out on something then it will pop the fuse. The wires under the seat can get crimped in the rails or inside the lining of the seat. Happened to me once and the fuse only blew when my wife drove the car only. It was when she move the seat down (sometimes) and it would catch the wire just enough for it to ground when she hit a bump in the road. Your brake lights are also connected to a "brake switch" on the brake pedal. Check these wires.

The fuse that's blowing is the one under the hood (30a) right?
 
Yeah, I had a similar problem as well awhile back.

I actually threw in a 30 for a while back and it didn't blow, whereas 15s (which is what it is supposed to be) and 20's were blowing after 10 minutes of driving. Anyways it got me to work that day.

Not sure what the exact cause is - but doublecheck the fuses and lemme know!
 
well, when we put a 30amp fuse in under the dash, it didnt pop, but that caused the fuse under the hood for the cluster to pop. with a 30amp fuse in both, neither one would pop, but during driving, you cans ee the cluster kind of dimming like it is shorting on something. it is a band aid solution, but i wouldnt feel comfortable driving the car that way.
 
I would start by disconnecting each item on the circuit and then plug them back in one at a time (while using your mojo to try and make the fuse pop). Once you find a device that is plugged back in and makes it pop, you have a bad circuit there.

JR had some real nice points - that is where I would start first (I assume that his mentionings have already been checked from the time he posted to now).

Otherwise issues like this can be quite counterintuitive and very difficult to track down with a shotgun method.

Good luck.
 
we found it.....unfortunately after we went through about 25 fuses. we found it by a stroke of luck too. paul was under the dash looking for the switch that is shown in the schematic. and for some reason he pushed in the clutch pedal. there happened to be a good fuse in there by a stroke of luck and he saw a spark and the fuse popped. there was a group of wires that had worked loose from the plastic clip and were sitting on top of the clutch pedal assembly. over time the pedal wore through the insulation. some electric tape and a zip tie later and all is well. unfortunately it took a ton of time and caused a lot of frustration before we actually found it. thanks again to everyone who gave their input.