Hey folks, anyone else have this problem, and more importantly a FIX for it??? My 88 Ranger headlight wire harness MELTED and the dark brown wire and the tan wire with the brown stripe burnt badly. The tan was the worst. The whole area around the tan wire with the brown stripe was melted away to nothing. I went to the local junkyard to get another harness end to patch in, and the ones in the yard were burnt similar to mine, but most not as badly. I finally found an acceptable replacement in an 89 F150, which was also scortched, but not totally fried. The wires affected run the marker lights, tail lights and trailer lights. I DO run a trailer, so there is extra current drawn through these wires. How can the power useage through the switch be cut drastically and still run all the lights without heat generation? How would I go about wireing in a relay??? HELP!

 

I think you can buy pre made relay harnesses. One terminal goes to ground, and the other two connect to a positive power source, usually the positive post of the starter relay. The best relays to buy are the relays like the OEM Ford fuel pump relay. You can get them with all five terminals. Use standard spade plugs, or ****** the plug from some ford trucks. Wire the coil in to the circuit and the ground terminal to a good ground. Wire a new hot terminal with an inline fuse direct from the battery. and run it to the relay. I don't have a schematic, which would probably be helpful. If you are familiar with wiring, you just want the original circuit to just power the relay, and power the lights off the battery when the relay is activated.

 

Use a relay like Bear said, also a heavier wire and make sure all of the connectors are TIGHT. What usually happens is the connector loosens slightly, an arch starts and it is all down hill from there. Many times I have put a SLIGHT twist in the male half of the spade connector to make sure it has a good connection. Greg

 

I'll give it a shot. Would I use like size 10 wire for the main battery feed, and what fuse value would be best? I am guessing a 30A ? I could also run a similar circuitfor the tail and marker lights. A mechanic told me I probably need a new headlight switch, because Ford had a lot of recalls on them, and it's probably routing the electricity wrong internally. Thanks for the suggestions, I'm going up to Autozone to see what I can find for a relay this afternoon. Anyone else have these type of problems???

 

Well, at least 30 amp. For the headlights, you might want to run them unfused. The tail and marker lights are a much lower draw. Just add up the amp rating of each bulb in the circuit, and add 20% and that should be your fuse rating. You can round up slightly, but don't go too high.

 

Great rule of thumb! Add up power use and add 20%. I can do that.

 

First of all rewire. Old melt wires are very dangerouse