Poweralth Posted August 14 Share Posted August 14 A few weeks back after camping my brake lights went out, turns out it was just the 15 Amp fuse that blew. Not even a week later they go out again, this time it's just the switch on the brake pedal itself, then I blew a tail light and got pulled over for it. It's suddenly gone out again and it's neither of the previous problems, switched out the fuse and nothing, as well as messing with the plug on the brake pedal. I'm not sure what the problem could be now as the high voltage side of the lights works (blinkers and hazards work perfect) Has anyone had to chase a problem like this and have any tips or ideas as to what it could be? I'm extremely confused and annoyed at this. Link to comment Share on other sites More sharing options...
schardein Posted August 14 Share Posted August 14 A blown fuse is usually an indicator of a short to ground. How did the brake light switch fail? Did it show any signs of melting or overheating? If so, could be another indicator of a short. When the brake light switch was replaced, did you inspect the connector for damage as well? It may need replaced to ensure a good connection. When you say "blew a tail light", does that mean a brake light bulb? Or a rear parking/running light? A blown light bulb might just be normal wear. Having repetitive issues like this, I would suggest two things, first ensure the ground points are good. The ground point for the taillight harness is notorious for developing corrosion. Next, if you have ruled out the ground, fuse, and bulbs, I would start tracing the circuit and checking for power. The brake light circuit receives power all the time (the horn and brake lights both work even if the truck isn't running). You can use a simple test light to see if you have power at the brake light switch. If not, move backwards in the circuit from there. If you do have power, move forwards through the circuit, examining the harness all the way from the cab to the tail lights. Another place to look is the steering column electrical connector. Disconnect it and check the terminals in both sides. Clean them up if they look corroded. Just disconnecting them and reconnecting them may be enough to improve a bad connection. Your brake lights run through the turn signal switch in the steering column, so the issue could be there as well. Link to comment Share on other sites More sharing options...
Poweralth Posted August 14 Author Share Posted August 14 6 hours ago, schardein said: A blown fuse is usually an indicator of a short to ground. How did the brake light switch fail? Did it show any signs of melting or overheating? If so, could be another indicator of a short. When the brake light switch was replaced, did you inspect the connector for damage as well? It may need replaced to ensure a good connection. When you say "blew a tail light", does that mean a brake light bulb? Or a rear parking/running light? A blown light bulb might just be normal wear. Having repetitive issues like this, I would suggest two things, first ensure the ground points are good. The ground point for the taillight harness is notorious for developing corrosion. Next, if you have ruled out the ground, fuse, and bulbs, I would start tracing the circuit and checking for power. The brake light circuit receives power all the time (the horn and brake lights both work even if the truck isn't running). You can use a simple test light to see if you have power at the brake light switch. If not, move backwards in the circuit from there. If you do have power, move forwards through the circuit, examining the harness all the way from the cab to the tail lights. Another place to look is the steering column electrical connector. Disconnect it and check the terminals in both sides. Clean them up if they look corroded. Just disconnecting them and reconnecting them may be enough to improve a bad connection. Your brake lights run through the turn signal switch in the steering column, so the issue could be there as well. Where would the tail light ground point be at? I'm extremely dumb with electrical work so sorry if it's obvious Link to comment Share on other sites More sharing options...
Poweralth Posted August 14 Author Share Posted August 14 6 hours ago, schardein said: A blown fuse is usually an indicator of a short to ground. How did the brake light switch fail? Did it show any signs of melting or overheating? If so, could be another indicator of a short. When the brake light switch was replaced, did you inspect the connector for damage as well? It may need replaced to ensure a good connection. When you say "blew a tail light", does that mean a brake light bulb? Or a rear parking/running light? A blown light bulb might just be normal wear. Having repetitive issues like this, I would suggest two things, first ensure the ground points are good. The ground point for the taillight harness is notorious for developing corrosion. Next, if you have ruled out the ground, fuse, and bulbs, I would start tracing the circuit and checking for power. The brake light circuit receives power all the time (the horn and brake lights both work even if the truck isn't running). You can use a simple test light to see if you have power at the brake light switch. If not, move backwards in the circuit from there. If you do have power, move forwards through the circuit, examining the harness all the way from the cab to the tail lights. Another place to look is the steering column electrical connector. Disconnect it and check the terminals in both sides. Clean them up if they look corroded. Just disconnecting them and reconnecting them may be enough to improve a bad connection. Your brake lights run through the turn signal switch in the steering column, so the issue could be there as well. And to answer the questions: the brake switch just got unplugged from the pedal itself, doesn't look overheated the plastic just looks old and warped but granted I live in an extremely hot part of the US. The tail light was a brake light bulb it just was old I think but i still got pulled over for having a blown bulb and everything worked great after replacing the bulbs Link to comment Share on other sites More sharing options...
eaglescout526 Posted August 14 Share Posted August 14 Ground for taillights is behind the drivers side tail light assembly. If that was an issue which it might, drivability would be questionable as the fuel pump is grounded there too. Link to comment Share on other sites More sharing options...
schardein Posted August 14 Share Posted August 14 Like Daeson said, the ground is behind the driver side tail light. This diagram from the MJ electrical manual kind of gives you an idea. I don't have a good picture of it handy. For the brake light switch I have a couple comments. From the factory, there would be a clip in the hole that the brake switch goes into. This clip kind of holds it in place. It is designed so that the switch is just pushed into it for installation at the factory, which then sets its adjustment and holds it there. Sometimes, that clip is damaged or missing when the brake switch is removed or replaced. And sometimes when the brake switch is removed, the plastic threads are damaged to the point that it won't hold a good adjustment. Some replacement brake switches come with two jam nuts. The idea is to remove the clip from the mounting hole, and then use the two jam nuts to hold the switch in place and in adjustment. One nut is placed on each side of the mounting bracket. The second picture shows a switch with the jam nuts. Another suggestion would be to look at the fusebox again. A lot of owners of manual transmission trucks have problems with the clutch master cylinder leaking fluid onto the fuse box, which causes corrosion. This then turns into a headache with multiple problems. Is your truck a manual trans? (Tip: add some of your trucks info to your signature line like year, engine, trans, 2/4wd, short/long bed. This can help when people offer advice for an issue) Link to comment Share on other sites More sharing options...
Htchevyii Posted August 14 Share Posted August 14 I've had one of the wires break that attach to the switch, twice. The wire inside was broken, but the insulation was still intact. At least on my truck, there was a tight bent there. Link to comment Share on other sites More sharing options...
Poweralth Posted September 2 Author Share Posted September 2 I was able to fix the problem, on the switch pigtail connector I guess the ground wire just wasn't contacting it doesn't look all too broken but I guess being a little bent out of place is enough to make the brake lights not work, I just went to O'Reilly and got some crimp on connectors and those worked like a charm Link to comment Share on other sites More sharing options...
schardein Posted September 2 Share Posted September 2 Glad you got it fixed. The brake switch doesn't have a ground wire, it has power in and power out. Link to comment Share on other sites More sharing options...
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