Hot wiring - The 1947 - Present Chevrolet & GMC Truck Message Board Network

79gmcc15 · 01-20-2011, 03:17 AM

What would cause the wiring for the inside light to get hot to touch? It is hot from the light to past behind the seat. that was as far as my investigating went for today. un-plugged battery just for safety.

79gmcc15 · 01-20-2011, 08:59 PM

Oh, just remembered. The wiring was getting hot all the time. Key off, doors closed and light switch on dash forward and all the way right. Any ideas? The light has never worked since Ive had it. I have new door switches that I am planning on replacing weather permitting. I am wondering if the light switch in the dash is shot and shorting the wiring? I am not getting 12'v to light. Just getting really hot. I have a canopy on so I can not test the cargo light.

1tonchevy · 01-20-2011, 09:33 PM

Quote:

Originally Posted by 79gmcc15

Oh, just remembered. The wiring was getting hot all the time. Key off, doors closed and light switch on dash forward and all the way right. Any ideas? The light has never worked since Ive had it. I have new door switches that I am planning on replacing weather permitting. I am wondering if the light switch in the dash is shot and shorting the wiring? I am not getting 12'v to light. Just getting really hot. I have a canopy on so I can not test the cargo light.

Check all the wiring for splits,cracks or rubbed through the coating could be shorting out.

cableguy0 · 01-20-2011, 09:46 PM

A short in the system. Its either a bad ground or broken wire somewhere. UNhooking the battery was a very good idea.

*lakeroadster* · 01-20-2011, 09:51 PM

I agree with the "Bad Ground" being the fault.

Run a temporary ground wire from the light housing (assuming it is steel) to the battery negative terminal and see if that fixes the problem. If it does, it is a ground problem.

It's amazing the wierd stuff that happens when a circuit isn't properly grounded.

79gmcc15 · 01-29-2011, 05:00 AM

Ok, so I have been poking around with this thing for a couple days. And my gut feeling is that the socket it's self is shorting out. The connection in socket is loose * I can twist the wire around* and is warn out. It also gets really hot at the plug then it gets cooler the further away you go. It is almost warm by the time you get by the hood lever.

So this is what I have done so far:

I took the switch by seat belt off to find the plugs toast. Fixed that.

After fixing that I decided to ground the light plug to somewhere else. That did not go well, it fried my wiring. Also I have come to the conclusion that it is the ground wire that is getting hot. Partly because the wiring at the pillar switch is cold *the + wire*.

Then I changed both of the door switches. The driver door was all rusted out. After install, I noticed that fitment sucked, but I think I have it stable now. In the process of testing, the switch did shock me and blew the horn fuse. *I thought it was just the horn, now I know why my horn fuse was blowing all this time. I thought it was the relay. Now probably due to light problem.*

So I cut off the socket and tested the voltage. I am getting a steady 12 v at the wires using the light switch and opening doors.

Then I hooked up the light socket temperately with wire nuts. And took the test light and clamped it on the outside of the socket and grounded the the probe end to the cab. It was always lit, but it did dim when you turned on the light by switch on dash or by door.

For what its worth, the light socket is out of the housing right now during all the test. Though, I doubt that the housing provides anything more then housing the light. It is made out of plastic and not meant to be used as a ground.

Should I replace the light socket it's self? And what range of cars/trucks can I get this from? Is there some kind of over the counter fix? I would prefer new to avoid this again.

Thanks!

**hatzie** · 01-30-2011, 02:00 AM

Quote:

Originally Posted by 79gmcc15

After fixing that I decided to ground the light plug to somewhere else. That did not go well, it fried my wiring. Also I have come to the conclusion that it is the ground wire that is getting hot. Partly because the wiring at the pillar switch is cold *the + wire*.

Thanks!

The door-jamb switches should be the ground side of the circuit *the - wires*. If the jamb switch is on the +12v side of the circuit it will blow fuses and melt wires as you have discovered.

I made a quick diagram of how the dome light circuit should be wired. Switch states are with the doors closed and headlight dome switch off.

79gmcc15 · 01-30-2011, 03:15 AM

Thank you Hatzie!

I actually got everything working good! It was the bulb socket that was grounding out and shorting. There is no over the counter replacement. But when I went to a Old School NAPA, the guy behind the counter was able to hull out the socket and replaced the contacts with a new two wire two contact assembly. And now everything works like a charm! open doors, light! Turn on the switch, light! And most importantly, it is not frying my line! One problem down! Next is the cigarette lighter!

*lakeroadster* · 01-30-2011, 08:43 AM

Quote:

Originally Posted by 79gmcc15

I actually got everything working good! One problem down! Next is the cigarette lighter!

Not fixing the cigarette lighter may save your life?

ChevyC102007 · 01-30-2011, 11:57 AM

Still good to have one though LOL.

79gmcc15 · 01-30-2011, 02:29 PM

Quote:

Originally Posted by lakeroadster

Not fixing the cigarette lighter may save your life?

Yeah, no kidding right? I did want to fix the cigarette lighter first. Because my radio went out on me, so I use my cell and Pandora for tunes. Lol not only did I fix my light but I figured out why the fuse for the horn*because of the light* was blowing. It's been like this for 7 years.

Posted via Mobile Device

01-20-2011, 03:17 AM	#1
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Hot wiring What would cause the wiring for the inside light to get hot to touch? It is hot from the light to past behind the seat. that was as far as my investigating went for today. un-plugged battery just for safety. __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby

01-20-2011, 08:59 PM	#2
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: Hot wiring Oh, just remembered. The wiring was getting hot all the time. Key off, doors closed and light switch on dash forward and all the way right. Any ideas? The light has never worked since Ive had it. I have new door switches that I am planning on replacing weather permitting. I am wondering if the light switch in the dash is shot and shorting the wiring? I am not getting 12'v to light. Just getting really hot. I have a canopy on so I can not test the cargo light. __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby

01-20-2011, 09:46 PM	#4
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	Re: Hot wiring A short in the system. Its either a bad ground or broken wire somewhere. UNhooking the battery was a very good idea. __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

01-20-2011, 09:51 PM	#5
lakeroadster Account Suspended Join Date: Sep 2009 Location: High Plains of Colorado Posts: 2,485	Re: Hot wiring I agree with the "Bad Ground" being the fault. Run a temporary ground wire from the light housing (assuming it is steel) to the battery negative terminal and see if that fixes the problem. If it does, it is a ground problem. It's amazing the wierd stuff that happens when a circuit isn't properly grounded. Last edited by lakeroadster; 01-20-2011 at 09:53 PM.

01-29-2011, 05:00 AM	#6
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: Hot wiring Ok, so I have been poking around with this thing for a couple days. And my gut feeling is that the socket it's self is shorting out. The connection in socket is loose * I can twist the wire around* and is warn out. It also gets really hot at the plug then it gets cooler the further away you go. It is almost warm by the time you get by the hood lever. So this is what I have done so far: I took the switch by seat belt off to find the plugs toast. Fixed that. After fixing that I decided to ground the light plug to somewhere else. That did not go well, it fried my wiring. Also I have come to the conclusion that it is the ground wire that is getting hot. Partly because the wiring at the pillar switch is cold the + wire. Then I changed both of the door switches. The driver door was all rusted out. After install, I noticed that fitment sucked, but I think I have it stable now. In the process of testing, the switch did shock me and blew the horn fuse. I thought it was just the horn, now I know why my horn fuse was blowing all this time. I thought it was the relay. Now probably due to light problem. So I cut off the socket and tested the voltage. I am getting a steady 12 v at the wires using the light switch and opening doors. Then I hooked up the light socket temperately with wire nuts. And took the test light and clamped it on the outside of the socket and grounded the the probe end to the cab. It was always lit, but it did dim when you turned on the light by switch on dash or by door. For what its worth, the light socket is out of the housing right now during all the test. Though, I doubt that the housing provides anything more then housing the light. It is made out of plastic and not meant to be used as a ground. Should I replace the light socket it's self? And what range of cars/trucks can I get this from? Is there some kind of over the counter fix? I would prefer new to avoid this again. Thanks! __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby Last edited by 79gmcc15; 01-29-2011 at 05:04 AM.

01-30-2011, 03:15 AM	#8
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: Hot wiring Thank you Hatzie! I actually got everything working good! It was the bulb socket that was grounding out and shorting. There is no over the counter replacement. But when I went to a Old School NAPA, the guy behind the counter was able to hull out the socket and replaced the contacts with a new two wire two contact assembly. And now everything works like a charm! open doors, light! Turn on the switch, light! And most importantly, it is not frying my line! One problem down! Next is the cigarette lighter! __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby

01-30-2011, 11:57 AM	#10
ChevyC102007 Registered User Join Date: Sep 2007 Location: Emporium,Pa Posts: 248	Re: Hot wiring Still good to have one though LOL. __________________ "When you were born, you cried and the world rejoiced. Live your life so that when you die, the world cries and you rejoice." [Cherokee saying] 2001 Dodge Ram Sport 1500 4x4. (old ride) 1987 GMC V1500 Sierra Classic ("new" ride)



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