Brake light fuse blowing

[Sahara01]

I noticed my brake lights were not working the other morning. Checked the fuse and it had blown. I put another fuse in and it immediately blew when I tapped the brakes.

I have read several threads on this and tried to troubleshoot the issue with out any luck.

I do have LED brake lights that the previous owner installed and they have been working up until this point. I have done my best to track down a short or bare wire between the brake lights and switch. Everything seems to be wrapped up and protected well.

The blinkers work which seem to be on the same wire as the brake lights which makes me think there is not a short between the switch and brake lights if the blinkers are working.

I tested the switch and it seems to be working. Does anyone have a diagram on the switch there seems to be several wires coming into the switch. One of which is a pink/blue that has been spliced several times by the PO. Those connections look okay.

Any ideas would be greatly appreciated. I may just buy a new switch to see if that fixes it.

Thanks in advance!

 

[ac_]

@Chris can you post a link to the TJ manuals?

If you are blowing a fuse immediately when hitting the brakes, I would guess you have a direct short. Which since you said everything is covered nicely I am betting something got hot and melted the insulations somewhere where the positive and ground are wrapped next to each other. Curious does pulling the e-brake blow the fuse or only hitting the pedal?

I would definitely go back over what the PO did. You may want to unwrap all of those connections and re-wrap them so you know that they are good. Whatever the problem is you have power shorting to ground when you hit your brakes. Now you need to find that.

 

[T Crawford]

Chasing one of those issues now with a friend no brake or turn signals we have identified the 12v wire from passenger fender fuse box was (brown/red) was only getting 6 or so volts to the steering column tracing it down seems to be in the loom from the firewall to the fuse. Good luck these are no fun. Ebay has this wire harness foe $770 discontinued overstock

 

[T Crawford]

Get the factory service manual under the how to guide scroll through all of the pages and you will learn a lot. Shows wire path and splicevlocations and testing parameters for headlight multi function switch

 

[Chris]

@Chris can you post a link to the TJ manuals?

Jeep Wrangler TJ Factory Service Manuals (FSM) & Technical Documentation

 

[Sahara01]

Thanks guys I’ll be back at it today.

 

[Sahara01]

Well now the fuse is not blowing. I don't feel like I fixed anything.

I preformed several continuity tests including on the switch and the wire that is spliced several times. Then put the volt meter on the fuse terminals and tried to find the short. What is odd is the fuse terminal for the brake lights only reads about 6. I could not find anything that would change that voltage. I threw a fuse in there for the hell of it and it won't blow anymore.

I haven't done anything recently but did check all the mods i.e. LED brake light connections, CB antenna brake light mount. Only other thing is we got hit by a 3 day rain storm and the jeep had a decent amount of water sitting in it. First time I noticed this was on one of the rainy days.

 

[ac_]

Well now the fuse is not blowing. I don't feel like I fixed anything.

I preformed several continuity tests including on the switch and the wire that is spliced several times. Then put the volt meter on the fuse terminals and tried to find the short. What is odd is the fuse terminal for the brake lights only reads about 6. I could not find anything that would change that voltage. I threw a fuse in there for the hell of it and it won't blow anymore.

I haven't done anything recently but did check all the mods i.e. LED brake light connections, CB antenna brake light mount. Only other thing is we got hit by a 3 day rain storm and the jeep had a decent amount of water sitting in it. First time I noticed this was on one of the rainy days.

Maybe water settled somewhere and not dried? It is a horrible think to track down, but keep some fuses handy and especially watch for it on rainy days. Or hose it down and see if you can replicate it.

 

[Sahara01]

Well it started blowing fuses again already.

I did notice it looks like there are resistors for each LED brake light. From what I have read resistors should not be used and the flasher should be replaced or modified.

I think I will take a closer look at the resistors and see if they have fried anything.

 

[T Crawford]

What fuse did you get 6 volts on?

 

[Sahara01]

What fuse did you get 6 volts on?

#2 stop lamps it’s the one that keeps blowing.

 

[T Crawford]

Interesting on my buddy’s it was fuse 27 on the fender. And getting 6v the steering wheel multifunction plug pin 11 I think brown/red wire

 

[Sahara01]

Okay think I have this wrapped up and solved.

I kinda forgot this was a tow vehicle for the original owner after I pulled the tow hitch off and put a winch and bumper in.

So the rear brake lights were connected to trailer wiring and each light had two diodes linked it. A real cluster of connections. I pulled the diodes out one side of one seemed to be dead. So I just hard wired everything with out any diodes.

Next I cut the blue and pink switch wire that was spliced 3 times and made a single connection here.

This seemed to work fine for awhile then blew a fuse again.

Finally I pulled the 3rd brake light wires from the tub buttons. This is what I really think solved the issue although there are no wires on the tailgate side.

So far so good!

I rewarded myself and the Jeep by putting a new set of duratracs on order.

Think I am going to switch to some 15x8 black wheels also.

 

[W2JKD]

The problem must be a short in the cabling for the third light since the fuse only blows when you press the brake pedal but the turn signals work which means that the regular tail lightbulbs are functioning properly. The only difference is that the brake light power is also the third brake light located above the spare tire. Also, I noticed that the wiring for the regular tail stop and turn lights is on the drivers side of the chassis, but, the third light is in a bundle that runs through the passenger side of the chassis. I have the same problem and will alert all if I find the cause

 

[Jack_Stefan]

The problem must be a short in the cabling for the third light since the fuse only blows when you press the brake pedal but the turn signals work which means that the regular tail lightbulbs are functioning properly. The only difference is that the brake light power is also the third brake light located above the spare tire. Also, I noticed that the wiring for the regular tail stop and turn lights is on the drivers side of the chassis, but, the third light is in a bundle that runs through the passenger side of the chassis. I have the same problem and will alert all if I find the cause

Any luck? Currently dealing with the same issue

 

[Chasitek]

Any luck? Currently dealing with the same issue

Also just stumbled onto the same issue if you have a solution?

 

[macleanflood]

Divide and conquer...check the brake switch, check the tail lights individually for shorts at the connectors.

Factory service manuals and a multimeter and some time.

You can do it!

-Mac