I have an 84 f150 that when I bought 3 weeks ago didn't have working clock or courtesy lamps. after searching I found the fuse diagram on the internet and sure enough there was no fuse in the slot. after putting one in they all worked fine until 2 days ago when they went out again. the fuse had blown, so I replaced it, blown immediately. I've 10,15, and 20 amp fuses and they all arc and blow as soon as I plug them in. any ideas?

 

Pull the courtesy lamp fixture and inspect of melting or damaged wring.

 

Also pull your door jamb switches and see if there is a wire off. A lot of Fords run hot thru the door jamb switches to operate the dome light. Disconect the negative battery cable before hand in case it is off or it will short out possibly. Never use a fuse bigger than it calls for because wires will melt before fuses blow in some cases. Don't ask me how I know. Steve

 

wouldn't the clock stay working though?

 

Not if it is on the same fuse. Check the diagram and see if they are together.

 

Courtesy lamp is on with the cigar lighter I think so you might check that also

 

cigar lighter/horn are on thier own fuse, courtesy lamps are on thier own as well according to wiring diagrams, but I admit, not real familiar with reading those.

on the backside of the fuse box the light green/yellow wire goes to the fuse location, from there it goes into a bunch of wires wrapped up, and then I lose it. under the hood there are several harnesses that dead end to nothing and even a few wires that do the same, so I'm pretty sure I have a short somewhere, just don't know which wire to look for under the hood, can't see any light green/yellow one under there.

 

Take the courtesy light apart, put a fuse in and see if it blows.

 

Pull your door pushbutton switches out and see if a wire is off. They are wired on a hot circuit and if the wire is off and touching metal it will blow the fuse.

 

Maybe run a new wire up to the light.

 

The only reason to check under the hood is to look at the under hood work light if you have that option.

Check the glove box light

Check the domelight that was mentioned several times in the above posts

Check the cargo lamp if you have that option.

Check on either side under the dash for more lights if you have this option.

If all the lights check out ok, I would pull the rocker panel cover off the driver's side, and check the wiring that runs in the channel and then behind the seat area. The wires sometimes get corroded in this area.

 

these are all considered courtesy lights, so to respond to your post, NONE of them are working, the fuse arcs and blows before even pushing it in, it's not a bulb or lamp problem, there is a short in the wire somewhere, or a ground that is disconnected, or something to that effect.

 

You're right, it probably is a short. Now you have to find it. If someone doesn't beat me to it, i'll dig out my wiring diagrams to tell you which wire controls what.

 

thank you, I've got a chiltons manual, but I don't know much about electrical yet except when it doesn't work, so if you find your diagram and tell me which colors to trace, that would be a huge help.

 

I think the short is under the sill plate as mentioned before.