hey i have a 1993 dodge cummins 12v i have a flat deck on it with marker led around it and so on the dash light and all lights were working well.... untill 2 days ago i was driving and then i noticed my dash lights went out i didnt think much of it i thought it was just a fuse so i got a new fuse but when i go to put the fuse in it will sparks and will light everything up but the driving light switch wont turn it off and then my fuel gauge will stop working not sure what to think after looking under the fuse box it now has melt a bit of the wire that comes off the horn / dash light fuse out let.... not good and when i will driving home today one of the wires that looked to be a main one melted as well and cut the motor off but i have fixed that by cuting the melted peace off and putting in a new one witch seemed to fix that fine ?????

 

You've got a short. No easy way around that one, you've got to chase it down and get rid of it before you burn your truck down. Make sure all of your fuses match the ratings called for on the fuse box. I've seen cases where fuses blow because of overload or bare, rubbing wires and people just stick a bigger fuse in the slot, causing the wires to get hot and sometimes melt into a big, bubble gum-shaped tinderbox.

 

ya i just have the fuse out right now and get the truck home before dark do you know where i should start to look ? or why there would be a short i had a 30 amp in it ????thanks

 

I'd start with the dash harness. The headlight switches in our trucks carry all of the load (which is why it's not a good idea to add anything to that circuit). Even carrying the headlight load causes them to overheat and fail occasionally. Your best bet is probably to pull the speedometer assembly and switch. Once you have everything unplugged, take a peek back there and look for evidence of hot spots or tears in the wire insulation. It's pretty easy to spot if you take your time and weed through the wires carefully. The issue could very well be in the switch, itself. Not a bad idea to go ahead and replace it while you've got it out. It's between $20-$30. BWD isn't great anymore, but they're still probably your best bet unless you buy a n.o.s. unit online.

You might also consider installing a relay setup. Much easier on the switch and doesn't stress your factory harnesses.