Hey All,

I have a 2006 F-150 5.4 FX4 and tonight I was changing a compressor for a horn and the live wire for the horn touched the frame and the truck died and I cant restart it. I am going to check the fuses tomorrow but I was wondering if someone might know a trick to fast track or maybe make sure I dont miss something suggestions I would appreciate any help all.

Thanks Doug

 

What happens when you turn the key to Start? Does it crank, just click, or do nothing?

You definitely need to check fuses.

 

it cranks just wont start.

 

Changing a 'compressor' for a horn - sounds to me like some after market wiring has been done.

Be that the case, it would depend totally upon WHAT the aftermarket device was connected to for power.

But if it cranks over - just won't start up. A logical 'assumption' might be power was taken from either the circut powering all fuel injectors through Fuse F34, or from the circuit powering all Coil On Plugs through Fuse F102. They are both hot in the "ON", "START" and "RUN" key positions.

You could narrow THAT down quickly by turning key on, take your VOM and see if you have "Standing 12v" on common side of all Injectors AND COPs. If one is dead, look at the above mentioned fuse. Otherwise - it's Check Fuse(S).

 

The most logical assumption is that, if you shorted a HOT wire to ground, is that you either blew a fuse that is critical to engine operation or you let the magic smoke out of something else equally important.

 

Like you G O T T A . . keep the 'smoke' _IN_ that PCM and don't let it out. LOL

Hopefully it is adequately protected by a fuse somewhere --- depending on where power for that air horn compressor was picked up from.

 

so I found the fuse and replaced it...but now sometimes the truck will start and sometimes no...if I take the neg terminal off for a few min and then re attach it it might start or it might not...I will try replacing the PCM relay even tho I have swapped it and it still sometimes will start or not....I am wondering if the Neg terminal has a bad connection??? just an Idea

 

WHICH exact fuse was blown?

 

fuse #9

 

Which is for..........?

Owner's manual will tell you, if you don't have one, download it.

https://owner.ford.com/tools/account...r-manuals.html

 

fuel pump and injectors