FireMedic1

Recently I have been having trouble starting my truck. I turn the key and nothing happens, not even a "DING" when the door is open. I figured out that the Ignition Switch Feed fuse, spot 102 and was a 20A, was blown. I replaced the fuse and turned the key and the instrument panel turned on but when I turned the key to the start position the fuse blew again. I was figuring its either a starter or a Ignition switch problem and possibly having a short in the line some where. Any input would be appreciated on figuring out what exactly could be wrong.

A dog

2004 F150 FX4
My #102 fuse blew while i was driving. I popped in a the 10 amp fuse from my power seat, drove 2min then one of my coil packs actually caught fire! I unplugged the coil pack after it had cooled down, and limped back home.

Mod (Ret.)

If the fuse is blowing, you have a short in the circuit. Putting in a larger amp fuse (as the above post points out) will only potentially cause a fire, electrical damage, or component failure. The wiring and electrical device are rated for a certain amp draw. The fuse is intended to blow whenever this draw exceeds the rated wiring capability, and/or electrical device draw.

Have you added any accessories lately/ Worked under the dash?

Could very well be the starter. Remove it and have it tested at your local parts store.

Could also be a wiring short.

JustBill

I think I'm having ignition problems too. I changed my oil today and when I went to crank it, nothing. Dead batt I hought. Got a jump from neighbor and headed to parts store to ck charging system. Made it half way and truck died. Nothing. Key won't even turn to try and start truck. I'm stuck guys. What am I facing here? Need help....thanks....ooopps. I got an 03 f150 4.6....

redfishtd

From your other posts . Change your signature to show this and other things about your truck . It helps to know if you are in the desert or in alaska .
For instance I have some wiring diagrams for an 05 f150 it may help some .
Do not bypass fuse you will cause damage .

redfishtd

Does it blow on insertion of key , acc ?, run ?, or start. Give it a little time on each position .
This circuit goes to a lot of places . Notice it does power up all cops , they have 12v standing on them--the pcm pulses the ground on the other side of the cops. . So you have a lot of exposure on the top of the engine .
You should also note that it goes to the shifter mech on the transmission on its way to the starter relay . That area under truck can be troublesome .
I have some tricks to work on this but I don't think your electrical know how is that good . So its hard to lead someone when your not right there . No offense intended .
One trick is to replace fuse with 12volt bulbs in parallel a few to allow 10 amp flow without lighting if there is no short . But you definitely have a short so they will light until you find the short . This is an advanced method and not for beginners it takes some expertise.
Your best bet is to use an ohmmeter but not on a live circuit . Many people don't know how to use it . You may need to get some pro help .