1991 Ford F150 - AC fuse melted

ford
f150

#1

I have a 1991 Ford F-150. AC was running fine then one day the fuse melted. Badly. Melted the area in the fuse box!
I cannot replace the fuse.
Anyone have this problem?. Any suggestions on what I can do?
Do I have to replace the whole fuse box and harness?
Can I just replace the fuse box?


#2

It is possible to run a circuit external of the fuse box . . . I’ve done this from time to time

That said, you have to consider WHY the fuse melted

Is this the fuse for the ac compressor, or the blower?


#3

@db4690 is right, you need to find the reason the fuse melted first or you could have a truck fire on your hands.

Yosemite


#4

A close inspection for damage elsewhere in the circuit is needed. A wire with the insulation melted off could cause a lot more damage when a fuse is installed.

And was the fuse the proper amperage?


#5

The current required to run the AC is fairly high so if there is even a slight fuse connection resistance involved that causes a voltage drop at the connection and that causes heat to develop at the connection due to the power dissipation. There could be a problem with the compressor clutch that is causing excessive current draw or it could be there was just a bad fuse connection that caused the issue to happen. I would guess that this happened just because the connection was weak and heat built up at the fuse connection. To fix the problem you can either replace the panel or just get a single fuse holder and tie it to the same power bus the original one was connected to and tie the other end of the new fuse holder to the wire that goes to the load for that circuit.


#6

It takes some testing to decide if the fuse box can be saved, and the problem area bypassed or not. If it doesn’t cost too much to replace the fuse box that’s what I’d do. As posted above, before doing that, figure out why the current in that circuit is so high it melts the fuse.


#7

To answer your question about replacing the fuse panel, you should be able to replace just the panel itself if you want to. The panels usually have sockets on them for the wire harness plugs to fit on to them. The less expensive repair method would be to just bypass that circuit using a single add in fuse holder to make the repair with.


#8

Cougar

    August 6

To answer your question about replacing the fuse panel, you should be able to replace just the panel itself if you want to. The panels usually have sockets on them for the wire harness plugs to fit on to them. The less expensive repair method would be to just bypass that circuit using a single add in fuse holder to make the repair with.


#9

Yosemite

    August 5

@db4690 is right, you need to find the reason the fuse melted first or you could have a truck fire on your hands.

Yosemite


#10

That bypass technique was used by my Honda dealer on my 1976 Civic CVCC decades back. Excess heat around one fuse in the fuse block to the left of the steering wheel was the symptom. It’s a very straightforward and not so expensive fix.


#11

Compressor. the blower still works.


#12

It’s possible the fuse and fuse block melted because your compressor is no good, shorted, etc.

If you were to solve the problem for the blown fuse and wiring, whatever it may be, you could run that circuit external of the fuse box, using the appropriate size in-line fuse


#13

Is there another fuse for the compressor, located on the wire to its clutch?