macgyver681

1997 F-150 XLT 4x4 4.6L Towing package

I just bought this truck and previous owner was having trouble with brake lights. He wasn't able to fix it. I have inherited that problem.

Basically the yellow ABS light is always on. As soon as you touch the brake pedal the fuse blows. No brake lights in the rear or third brake light.

So far to try and figure it out I have disconnected:
BOO (Brake on off switch) tested and jumpered OK
Cruise control actuator (under hood)
Crusie control brake sensor (on master cylinder)
RABS valve electric connnector (under master cylinder)
Multi Function switch(turn signal/hazard)
3rd Brake Light
Factory towing harness (Rear)
Factory electric brake controller(Cab)
Cut Light Green and Light Green/Red wire to brake lights under cab in harness
Removed aftermarket alarm
Checked Fuse in small fuse box under hood for towing package

After each of these I tested the brakes by installing a new fuse and jumpering the BOO connector to simulate pressing the brakes. Every time the fuse pops immediately.
They are all still disconected and it still blows the fuse. I'm running out of ideas and the forums aren't giving me any new ones.

Any help is appreciated. Thanks

A7X

C'mon Macgyver you don't have a piece of gum, a paperclip and a straw??? we all know you can figure this out

Just kiddin man... well there's a short somewhere, Hmmmm have you pulled the kickpanel and inspected the wiring there yet?

A7X

Also the harness thats on the top of the pedal is known to let a wire or two go without many signs of it... unplug it and give a wiggle and see if all the wires are snug and aren't separating...

Sorry if you checked this stuff, it sounds like you know what you're doing

macgyver681

Gum blew the fuse also, can't find a paperclip in my entire house.

Pulled whole underside of dash, no obvious signs of a short. Lots of wires and no good starting place I guess.

macgyver681

Sounds like your reffering to the BOO switch. Tested and jumpered it. Its fine and not the problem. Thanks tho.

A7X

LOL, off to office max I guess
Yes I was referring to the brake on/off sorry...
you pulled the kick panel by the rocker? everything that runs to the back goes through there as well as grounds...

macgyver681

Checking kick panel...

The blue meanie

Maybe the previous owner replaced the fuse with the wrong size and you're just repeating the process?

A7X

Cool, keep us posted... We'll chase that problem out of there, even if I gotta go pull my truck apart lol

macgyver681

No. I checked the manual, its the right size.