Fuse 13, brake light keeps popping
 

I just replaced the front gas tank, pump and sender because the pump stopped working and I found a small hole in the tank. Everything was fine before the new tank, I just ran the back tank.

Now every time I apply the brakes fuse 13 pops. I disconnected the new sender/pump but it still pops the fuse.

I didn't do anything except the new tank and spray a little bug killer around the front and rear axles because Widows were trying to make it their home.

Anyone have an idea where I should look for the short?

Thanks.

Hi Craig,

The fuse popping could be a broken wire leading to the brake light switch, or a defective brake light switch itself.

When this happened to me, I had no brake lights so I investigated. I found a blown stomp lamp fuse and a broken wire leading to the brake light switch located directly underneath the steering column in the cab. It's right by the interior fuse panel underneath the steering wheel.

I would check all the wires in that area first because your problem sounds like a bad connection. Usually if the brake light switch goes, you'll have trouble getting out of park.

Let us know if you find anything out of the ordinary.

I think someone had spliced in a wire to the brake switch in the past because there's a small cut white/green wire coming out from electrical tape at the switch.

I think I must have done something back by the fuel tank connections.
I can't take it out of Park but I think that's because the fuse is blown.

If you can't get out of park, the fuse is blown and your brake lights don't work, I could almost guarantee the brake light switch is your answer. Mine just randomly went bad and it made me think I did something wrong the last time I repaired something, but that wasn't the case.

I replaced the brake light switch and the truck would then shift out of park.
I repaired the broken wire and replaced the fuse, and my brake lights worked again.

The brake light switch is a very cheap part (less than 10 bucks) and it installs in 5 minutes. It might be worth your time

But if you insist it's something you did while doing the fuel work, double check everything you connected/disconnected one more time to make sure they're properly placed. Also ensure you didn't damage anything electrical while you did it.

I forgot to say in my first post that along with #13 fuse blowing, the ABS light is flashing.

I replaced the switch and there was no change.

I thought I might be able to take it out of Park before putting my foot on the brake pedal and popping the fuse, but the gear shift won't move.

That's odd. Did you do anything about that odd wire?

Without your foot on the brake, the truck won't let the column shifter move. Usually if the switch is bad, the truck thinks your foot isn't on the brake even if it is. I'm shocked that the switch didn't work because these were literally all of my symptoms when this happened to me. My ABS light was on, too..

I'd do some more investigating in that area. In the meantime, run a self test. These are very helpful and can help you narrow down any issue you might have. Here is a guide on how to do so:
Ford Fuel Injection » How To Run a Self-Test

The links explains it all, and at the bottom of the page you'll find a link to a list of the codes and their meanings. Your computer probably has a code stored about something to do with this. My guess is you'll get code 536. Perform this test when you get the time and tell me the results. If the link I provided confuses you, just ask me any question you might have.

While I don't believe it be an easy thing to do (haven't dropped a front tank lately either), any chance you pinched the wire harness between the tank and frame for example?

Wire harness feeds rear lighting and front fuel tank reside same side of the truck.

Take a second make sure you can move the wire harness around freely as it passes by the front tank.

I just cut that wire a little shorter.

Codes on KOEO were 111
Codes on KOER with a pretty cold engine were 653, 853 and 663.
Codes on second run with a warmer engine were 548 or maybe 538. I might have missed a blink. It gave that code 2x and that was it.

No brake system codes even though the another fuse blew when I pushed the pedal during the test.

The wires for the middle tank come across and go to the inside of the frame rail, but they aren't pinched.

I'm stumped.

For the Key on engine off (KOEO) 111 = system pass, which is good.

What's bad is nothing has pointed us in the direction of your brake light problem.. I'm stumped as well.

Yea doubted it be possible even likely due to the way the harness is routed, worth a mention only because you dropped the front tank and didn't suffer the issue until you had.

Try this once, unplug the brake light switch at the pedal then replace the fuse, turn on the 4 way flashers see if the fuse blows or the lights flash as they should.

If not it greatly reduces the list of possibilities narrowing it down to a select few.

Don't necessarily even have to unplug the brake light switch, turn on hazards do not press brake pedal see if fuse blows or not.

I'll try that but I've got to go buy more fuses.

when mine was doing the same thing, I traced it to the wiring harnes on the front of the truck, but I have a plow setup on mine and the wires had broken and were grounding out.

I keep thinking it must be the sender/pump wiring. The Spectra Premium pump/sender comes with a female ind and you have to cut the female off the harness and splice on this new connection. The directions don't list all the color wire connections but I thought I was able to figure it out.

I did find an picture from an older F150 and the wires were the same as mine so I thought I got it right.

Maybe there is a common ground?

Are these right?

Pump power=red
Pump ground=orange
Sender power=blue/yellow
Sender ground=black

Hazards, turn signals, headlight/taillight all function normally.

fuse doesn't blow using hazards tells us the circuits to the lights are fine, nothing grounded out that shouldn't be.

Unplug the rabs module, open glove box squeeze in sides at top to allow box to fully tilt down. Module connector at upper right corner as seen over glove box, module is black box approximately 4" high by 5-6" long.

Unplug it then hit your brake pedal see if the fuse blows.

If not fuse does not blow first thing I'd check the wiring down at the rabs valve itself, valve is inside frame rail say directly under your feet while seated behind the wheel, inspect harness see if find any damage.

If find nothing obvious there replace fuse pull code/s for rabs system let it tell you where the problem lies.

If fuse blows rabs likely ain't it move on to next circuit.