1994 Chevy Silverado Headlight switch

Tiny
355CID
  • MEMBER
  • 1994 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 13,500 MILES
My 1994 C3500 keeps melting the parking lamp circuit in the headlight switch. I checked that it had the correct fuse and it does. It calls for a 20A fuse and it doesn't blow the fuse. The wire that supplies power to that part of the switch has been really hot and the wire coming out of the switch on that circuit is almost metled as well. I stuck a 10A fuse in that circuit and it did NOT blow the 10A fuse. We tow a trailer with it sometimes but all the wiring checks out and it should blow the fuse before it melts the switch if there is a short somewhere. I'm stumped! Where do I go from here? Thanks.
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Tuesday, June 1st, 2010 AT 5:21 PM

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Tiny
CARADIODOC
  • EXPERT
Hi 355cid. Welcome to the forum. Heat in a wire comes from current going through excessive resistance. The resistance will be too small to measure accuratly but you can measure the results of that resistance in the form of a voltage drop.

Use a cheap digital voltmeter to measure the voltage drop between the two wires for that circuit at the switch. Ideally it should be 0.0 volts. The more resistance there is, the more voltage will be dropped. If you find excessive voltage there, look for connector terminals that were overheated previously. It may be necessary to cut them out of the plastic connector body and replace them with individual terminals. I use crimp-type terminals but I also solder them for a better connection. You might have to cut off about 4" of each wire too and splice on new sections if they are hard from being overheated. Hardened wires are very difficult to solder to.

Caradiodoc
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Tuesday, June 1st, 2010 AT 8:23 PM
Tiny
355CID
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Wednesday, June 2nd, 2010 AT 5:14 PM

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