73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Electrical => Topic started by: GUITAR1989 on August 20, 2010, 05:27:45 am
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Hey guys hows it going. I got some autometer gauges and started wiring them up today and i came across something horrible looking :( theres a wire that has pretty much melted through the coating on it. I started following it back to its source but it was dark outside so this is all i could find out before i headed in for the night. from what i can see so far its coming out of the light switch that controlls the interior and head lights its black and goes down toward the fuse panel. my guess is its a ground thats taking to large of a load for its gauge or something along those lines. so does anybody know how i should fix this. please be descriptive with your explanation ive never done any car wiring before....all i know about wiring is what ive done on my guitars ha ha
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Take pics
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Dont guitars have strings?
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I assumed he meant electric guitar!
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ha ha yeah electric guitars. ok i got a pic of where the wire is coming out of the light switch
(http://i37.tinypic.com/2ewedmw.jpg)
the wire gets much worse than it is in the picture. at some points its melted all the way through the coating on the wire.
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Replace the switch and the pigtail. Check all of the associated wiring. Now would be a good time to upgrade the harness to a relay operated headlamp circuit.
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so was it the switch that caused this wire to melt? If i get a new switch and rewire it the new wire in that exact spot wont melt again right? could there be anything else causing the wire to melt? i just dont wanna blow 20 bucks on the new switch and have it melt the wires again :P thanks for your help by the way :) oh yeah what does a relay operated headlamp circuit do?
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I dont know if it is just a bad switch or not, but carefully trace all wires and make sure there isnt anything wrong down the line. x2 on the upgraded harness. The problem with this wiring system is that all the power goes through the switch, then to your headlights. Installing relays will take the load off the switch.
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ah i see. thats actualy really cool. it seems like that would keep my new wires from frying like these ones did seems like a great upgrade and a cheep one...my favorite kind. i wanted to have my new gauges in but i guess ill hold off so i can get a new switch and wire it up to a relay :) well im off to search for some info on how to wire that up i guess :P thanks again
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http://73-87.com/7387garage/exterior/headlight_relay.htm
Or you can buy a kit.
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Thanks beastie, that will help me out a lot, as I am sure a lot of other plp too.
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http://forum.73-87chevytrucks.com/smforum/index.php?topic=14640.0
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I ordered that kit from . Theres a video of a guy installing it on a 73 stepside and it looks easy. ill post some pics of my gauges once i get them in so you guys can take a look :) thanks for the help btw vile and beastie both of u have helped me alot on here and i really appreciate it
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Glad to help. Just remember to trace that circuit to determine what caused the circuit overload and make sure you are using the proper circuit protection. Wiring harness meltdowns are more common in Fords than GM's. All manufacturers are using relay operated systems now.
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X2 on finding the cause.
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so i traced the wire and found out that the charred blackish melted pos was 18brown-9 at one point :P also where the blue wire is suppose to be on the switch pig tail there isnt one. (http://i36.tinypic.com/kbzxon.jpg) whats weird about the wire is its only melted up to the firewall..the point past the wall is perfectly intact. im thinking i can just get a new pig tail and rewire it with the blue wire. my switch still works fine+im hurting for cash so i took it apart and cleaned it up so i can keep using it. if the wires melt again then ill replace it but for now i just dont have the cash. i ordered the relay kit for the lights so ill be putting that in also.
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did you check to see if the melted wire got cut at the firewall and shorted out ?
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No not yet its covered up in a ton of this rubber gunk right where it passes throgh the fire wall. Tomarrow im going to get it cleaned up and check it out. since its pretty cheap im getting a new headlight switch/plug and the Heavy duty Headlight relay kit from ;D http://www. .com/icatalog/cc/full.aspx?Page=70 After that its on to finding out why my gas gauge doesnt work...im sensing another wirng problem in my future. The guy i bought the truck from really loved electrical tape and faulty connectins. Someday ill get to put my new gauges in ::)
Oh yeah also i found out that the blue wire that was missing from the plug was suppose to connect the light switch to the dimmer switch...do you guys think thats why my brown wire melted? What are the repercussions of that blue wire not being wired to the dimmer switch?
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hey guys :) i finally got the switch and pigtail to fix my melted wire problem. I traced the meted wire down to the firewall junction blockl. im having some trouble gettin the wires out of the block. heres a picture of the wires in question. so if anybody knows how to get these suckers out id really appreciate your input. can this block be pulled apart so i can see whts going on inside of there. im thinking the problem may be hidden inside that block since the melted wire 18 BRN 9 stops inside there and the wires coming out of the other side connected to it are perfectly intact. also is there anything in there aside from the 2 wires connecting..like a fuse or anything else connecting them that may hav failed and caused 18 BRN 9 melt?
(http://i53.tinypic.com/rrobyh.jpg)
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I'd like to know as well :) That brown wire is your park lamps. I believe it splits at the firewall to where it goes to the front lamps, and the rear lamps. The wire that is melted is I believe carrying the currrent for both the front and the rear sets of lights. Do you have anything funky going on with your park that might cause a large current draw?