Bad wiring problem

[feifong]

I have an 83 convertible with a wiring problem it starts up fine but its where the starter solenoid fusible link goes is where the problem is mainly. My 83 doesnt have a fusible link where most mustangs are supposed to have one. Instead mine has a wire that goes to a regular fuse is this ok to have? The problem is if i put a 5-10 amp fuse it pops them before i turn the key but if i put a 20 or 30 amp fuse it takes about 1 min before it pops them. If this fuse is busted the car wont turn on or anything. It is a yellow wire that is somehow connected to the brakes and headlights. I also get small poofs of smoke under the dash and the dash is already halfway off i cant tell where its coming from. Could a bad ignition switch do this?.

[TWR2003]

You must have some kind of short circuit somewhere and probably a previous owner had the fusible link blow (as it should if there is a short) and replaced it with an inline fuse. Fusible links are basically fuses in that they will permanently 'open' (the wire inside melts) if there is a short on that circuit. The different between fusible links and fuses is that fusible links are typically 'rated' as a wire gage and are typically two wire gages smaller than the wiring of the circuit they are protecting. That yellow wire going to your solenoid is typically 12AWG and therefore the fuse link is two gages smaller at 16 AWG. As you stated fuses are rated in amps (ie 10 amps, 30 amps, etc) based on the electrical current load the circuit is designed to handle.

All I can say is you need to find the source of the short circuit and fix that instead of trying larger and larger fuses. Then I would replace that inline fuse with the correct sized fuse link per factory specs. I do not mean to minimize the effort you may need to use to fix the problem as finding short circuits can be very difficult and time consuming.

Good luck.

T

[jrc347]

A Common joke we all have in the shop when dealing with short ckts is to put bigger and bigger fuses in till you find the short..... Meaning that the wire will eventually catch on fire exactly where the short ckt is. I hope I don't need to tell you that this is NOT a good idea. The wire will eventually catch on fire (along with the car). Anyways.... That yellow wire could definately be going into the ignition switch, which may be your problem. I would start by inspecting under the dash at all the wiring, specificly looking for that same yellow wire. Trace it down and unplug (if you can) everything that it goes to. Sometimes you get lucky and can actually see where the wire has rubbed through, or the component that has failed. Do you have a multimeter? That would make troubleshooting this problem much easier. Good luck and let us know how it turns out.

[85LXDRVR]

The wiring schematics for the 83' are available on this website. I would suggest reviewing them. It may help you to isolate (and repair) the short in your electrical system.

Mark B...
85' LX
Bold Springs, GA.