1971 LT1 electrical Problem
Thread Starter
Instructor
Joined: Dec 2013
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1971 LT1 electrical Problem
Hello
We have a unrestored 1971 LT1 coupe unmodified. Last week when we were driving the fuse for the dash light went out. No big deal. Yesterday I was driving for approximately one hour when the vette shut off. No sputter or engine miss, just shut off like turning the ignition off. Could smell just a hint of burned wires.The ONLY thing that worked was the HORN. Nothing worked, no radio, no hazards,no starter noise not even the click of the solenoid. Dead except for the horn
At the side of the road a nice man stopped who, it seemed, had his entire auto shop in the trunk of his car. He used his 12 volt tester and found power to a relay on the drivers inner upper fender about even with the valve cover. THAT is where he found a wire that had burned in half. After he spliced the broken wire together I drove the vette home. But the oil pressure gauge, volt gauge and temp gauge were not working. They were working before the wire melted
After checking I have found out the the relay on the inner fender is the Horn relay, which I will be replacing. But right now I`m not sure where to begin checking as to why did the wire melt in half. Any suggustions woud be greatly appreciated
Thanks
Rick
We have a unrestored 1971 LT1 coupe unmodified. Last week when we were driving the fuse for the dash light went out. No big deal. Yesterday I was driving for approximately one hour when the vette shut off. No sputter or engine miss, just shut off like turning the ignition off. Could smell just a hint of burned wires.The ONLY thing that worked was the HORN. Nothing worked, no radio, no hazards,no starter noise not even the click of the solenoid. Dead except for the horn
At the side of the road a nice man stopped who, it seemed, had his entire auto shop in the trunk of his car. He used his 12 volt tester and found power to a relay on the drivers inner upper fender about even with the valve cover. THAT is where he found a wire that had burned in half. After he spliced the broken wire together I drove the vette home. But the oil pressure gauge, volt gauge and temp gauge were not working. They were working before the wire melted
After checking I have found out the the relay on the inner fender is the Horn relay, which I will be replacing. But right now I`m not sure where to begin checking as to why did the wire melt in half. Any suggustions woud be greatly appreciated
Thanks
Rick
Melting Slicks
Joined: Mar 2005
Posts: 2,094
Likes: 298
From: Midlothian VA
Hello
We have a unrestored 1971 LT1 coupe unmodified. Last week when we were driving the fuse for the dash light went out. No big deal. Yesterday I was driving for approximately one hour when the vette shut off. No sputter or engine miss, just shut off like turning the ignition off. Could smell just a hint of burned wires.The ONLY thing that worked was the HORN. Nothing worked, no radio, no hazards,no starter noise not even the click of the solenoid. Dead except for the horn
At the side of the road a nice man stopped who, it seemed, had his entire auto shop in the trunk of his car. He used his 12 volt tester and found power to a relay on the drivers inner upper fender about even with the valve cover. THAT is where he found a wire that had burned in half. After he spliced the broken wire together I drove the vette home. But the oil pressure gauge, volt gauge and temp gauge were not working. They were working before the wire melted
After checking I have found out the the relay on the inner fender is the Horn relay, which I will be replacing. But right now I`m not sure where to begin checking as to why did the wire melt in half. Any suggustions woud be greatly appreciated
Thanks
Rick
We have a unrestored 1971 LT1 coupe unmodified. Last week when we were driving the fuse for the dash light went out. No big deal. Yesterday I was driving for approximately one hour when the vette shut off. No sputter or engine miss, just shut off like turning the ignition off. Could smell just a hint of burned wires.The ONLY thing that worked was the HORN. Nothing worked, no radio, no hazards,no starter noise not even the click of the solenoid. Dead except for the horn
At the side of the road a nice man stopped who, it seemed, had his entire auto shop in the trunk of his car. He used his 12 volt tester and found power to a relay on the drivers inner upper fender about even with the valve cover. THAT is where he found a wire that had burned in half. After he spliced the broken wire together I drove the vette home. But the oil pressure gauge, volt gauge and temp gauge were not working. They were working before the wire melted
After checking I have found out the the relay on the inner fender is the Horn relay, which I will be replacing. But right now I`m not sure where to begin checking as to why did the wire melt in half. Any suggustions woud be greatly appreciated
Thanks
Rick
So aftermarket (electric) oil pressure gauge?
"volt" (original amp) gauge relies on a wire running from the horn relay to the starter OR could have become overloaded when your wire burnt.
Thread Starter
Instructor
Joined: Dec 2013
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The gauges on the car are the factory gauges.
Oil Pressure
Water Temp
Battery
None of the gauges are working since the wire burned. All the gauges were working before the wire burned
Thanks!
Rick
Thread Starter
Instructor
Joined: Dec 2013
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There are two wires joined together with one electrical connection on the right face of my relay. On your picture it would be the connection on the face of your relay nearest your pink/orange wire with the black stripe that is on the right side of your relay. Both of my wires have a fuseable link. The wire that burned turned black ABOVE the fuseable link but past the link the wire is orange/pinkish on my car. Also the wire that is joined with an electrical connection to the burned wire at the relay is orange near the relay and then after the fuseable like it turns to a black with white stripe wire. I will try and post a picture
Thanks for all of your time and help
Rick
Melting Slicks
Joined: Mar 2005
Posts: 2,094
Likes: 298
From: Midlothian VA
OR, perhaps your hot/burnt wire cauterized your plastic oil line.
Last edited by Hammerhead Fred; Mar 30, 2015 at 08:14 PM.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
the oil pressure gauge on a 71 has nothing to do with electrical. It is totally mechanical with just a plastic tube running to the back of the gauge. The fuse able link is common on an older wiring harness to burn out but at least the OP gauge should work unless a line as said above got melted. If it got knocked off you would have a puddle of oil somewhere very quickly.
Melting Slicks
Joined: Nov 2003
Posts: 2,668
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From: St. Charles Mo
CI 5 & 8 Veteran
This is a shot from left field, but I have seen it happen more than a couple of times. Check your clutch pedal arm and make sure it is not scrubbing against your wire harness bundle underneath the dash when you disengage the clutch. It can scrap the insulation off wire and short it to ground burning fuses and stuff. Just an off the wall guess here.
Bullshark
Bullshark
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Thread Starter
Instructor
Joined: Dec 2013
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My error. The oil pressure gauge works. Sorry for the mistake.
Bullshark, You may have hit the nail on the head. I was downshifting to take a right hand corner and had pushed in the clutch and was braking at the same time when the vette died! I will check the clutch pedal and rods and also the brake pedal.
Thanks very much to everyone!
Rick
Bullshark, You may have hit the nail on the head. I was downshifting to take a right hand corner and had pushed in the clutch and was braking at the same time when the vette died! I will check the clutch pedal and rods and also the brake pedal.
Thanks very much to everyone!
Rick
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Sounds like the same symptoms I had on my 72 LT-1 it took a while to discover the wiring harness behind the dash had abraded through at 96,xxx miles the fuse link opened on the horn relay, I replaced it drove it for a while (including a 240 mile trip.) Then one morning before taking off to an autoX race, meltdown! Found the culprit after watching smoke rise on drivers side of the dash. Wiring harness had been against the cast iron steering column support since the UAW worker stuffed it there
Good luck in your search!
Good luck in your search!
Thread Starter
Instructor
Joined: Dec 2013
Posts: 104
Likes: 19
[QUOTE=Solid LT1;1589320642]Sounds like the same symptoms I had on my 72 LT-1 it took a while to discover the wiring harness behind the dash had abraded through at 96,xxx miles the fuse link opened on the horn relay, I replaced it drove it for a while (including a 240 mile trip.) Then one morning before taking off to an autoX race, meltdown! Found the culprit after watching smoke rise on drivers side of the dash. Wiring harness had been against the cast iron steering column support since the UAW worker stuffed it there
Good luck in your search
