Brakelight fuse?

[hellrazer]

OK I have checked bulbs replaced a circuit board and I am still chasing my tail. My 2005 Ext keeps blowing the 25 amp fuse under the hood I believe it is number 12. I replaced the questionable looking circuit board on one side and though I repaired the issue to find out once I drove the truck it blew the fuse again. I can not recreate the issue with out driving the vehicle I am completely lost any ideas?
Jason

 

[BlazingTrails]

OH MAN that may be a little difficult to track down. you could look at you brake light switch located at or around the brake pedal. inspect the wiring and check your leads with a Digital Multi Meter. also try unplugging each tail light one at a time and see if the problem goes away. If you narrow it down to one light pull the bulbs from that light and see if you can narrow it down once again. do your brake lights light up at all? how long before the fuse blows? I would also check the wiring under the back where the trailer plug is and make sure there is no damage to the wiring there. Report back with any findings and I will be glad to help


Good Luck

Edit; it may be a long shot but you could also look under the back seat on the drivers side and make sure there is no obvious signs of damage to the harness there as well.

 

[hellrazer]

I am honestly not sure how long it takes to blow the fuse as when it goes I am driving I can play with the lights till I am blue in the face with it sitting in the driveway and never have an issue. Everytime I think I have it figured out I take a ride and come back with no brake lights. none of the three light up once the fuse in the under hood fuse block blows. I have no idea there is no obvious wiring damage on the tail light pigtails and none that I can see on the trailer wiring as well ill take a better look at that in the am. my problem is the two fuses in the interior block are never affected only the underhood fuse. Thanks for your assistance,
Jason

 

[BlazingTrails]

Are the bulbs you use stock? higher wattage or anything like that? It seems like maybe it is blowing after the brakes have been on for a while. try putting something on the pedal for a while to keep the brake lights on and see if that helps you figure it out.

 

[hellrazer]

nope all regular 3157 bulbs haven't started modifying this thing yet that will be coming up at a later date. And I held the pedal for a while sitting in the driveway to no avail also tried activating the other lights with and without and cycling the brakes a lot as though my wife was driving it and that didn't do anything I think that's the most confusing part.

 

[kickass audio]

When you blow the fuse, does it kill the high stop light too or just the lower side lights? There are 3 fuses for it, one under the hood and 2 under the rear seat, under your rear seat you will find #16 is for your high stop light mounted above the window, and then #34 which is for your left and right stop lamps that are on each side of the truck at the back. Maybe what you can do is ride around the block real quick with one of those fuses disconnected and see if it blows #12 under the hood. If it doesn't then that tells you which one is part of the issue. I doubt that will change anything in all honesty. I would check for any broken or frayed wires where the stop switch is located on the brake pedal. It isn't a high possibility but still some chance that it is rubbing and shorting out on the frame that supports your dash. I had blew my fuse for the veh stop under the rear seat when I put in non CK style LED bulbs and it did not pop the one under the hood. Since you are blowing the one under the hood and not under the rear seat, it makes me believe your issue is under the dash with either the wiring or the brake switch which ive been told is a pain in the ass to get off our truck.

 

[hellrazer]

yeah it kills them all when it blows it is definitely blowing the one under the hood. I am heading outside to check it all out now see what I can find this thing is driving me nuts.

 

[freddyboy61]

Fuse #12 only goes to the stop light switch on the brake pedal, from there the power goes to the rear fuse box and to the flasher module. Since neither of the rear stop light fuses blow, the problem is either a wiring related issue or a bad flasher module. And since it is intermittent, it will be difficult to isolate.

 

[Robbabob]

Do you have another person to work with you? In the driveway, press the brake and put it in gear then put in park and see the result. Is it immediate or prolonged use? Not sure if that will tell anything. As many have said, probably the wiring from the pedal to the main box under the hood. If it has something to do wiht the shifter, will that tell you anything? Maybe....

Good luck!

 

[The_Roadie]

Typically those sorts of things have a wire with cut insulation touching sheet metal as a root cause. The shifter movement might be causing the intermittent short to ground that blows the fuse, as well as the movement of driving down the road. Intermittents are some of the worst issues to locate, and it might even be easier to fix it by cutting the fuse->brake pedal wire out at both ends, and running a bypass.

 

[hellrazer]

Well it appears to be the flasher module causing the issue. I drove the truck around most of the day today with the module removed and have no issues with the brakelights going out. Obviously I do not have any turn signals so I will be picking up a new flasher tomorrow morning and going from there. Thanks for the help guys hopefully this will be over tomorrow morning.
Jason