Strange Electrical Issues
Thread Starter
Racer
Joined: Nov 2006
Posts: 357
Likes: 8
From: Champaign Urbana IL
Strange Electrical Issues
I have a 1977 corvette thats having some issues.
Background: My GEN light was constantly on and eventually my battery stopped being charged from the alternator. Decided to go the easy route and get a 1 wire alternator. Problem solved. I recently installed halo lights up front that are tapped in with the running lights and work through a relay directly powered by the alternator. My low beams and high beams are also wired up through relays. On a 7 hour drive I stopped at a gas station and my engine wouldn't turn off (had the key out of the ignition). I have a aftermarket radio that has its constant power coming from the bat location on the fuse box. My dash lights went out at some point, ended up being a bad fuse, replaced but may have not been the correct amps. problem fixed.
The Problem: With the key in the on position, the dash gauges are on the whole time regardless the headlight switch position with no dimming effect. The running lights up front along with the halos come on correctly, HOWEVER they will dim and will eventually turn off if the switch is twisted all the way (this only happens with the key in the on position and the engine not running)
With the engine running and lights on nothing dims. headlights, running lights, and gauge lights all stay on full blast. Then when i turned the key to the off position the engine keeps running. The engine turns off along with all lights when I push in the headlight switch to the off position.
With the key out of the car and the engine off (haha i know, sounds ridiculous). The dash lights will dim appropriately and the running lights will stay on full power as they should. However the brake light/ seat belt lights also dim and the tach needle moves up with decreasing brightness of the gauges and down to zero with increased brightness of the gauges.
I'm going to check all my grounds today and from there I have no idea where to turn. Thanks so much. Hopefully one of you can point me in the right direction.
Background: My GEN light was constantly on and eventually my battery stopped being charged from the alternator. Decided to go the easy route and get a 1 wire alternator. Problem solved. I recently installed halo lights up front that are tapped in with the running lights and work through a relay directly powered by the alternator. My low beams and high beams are also wired up through relays. On a 7 hour drive I stopped at a gas station and my engine wouldn't turn off (had the key out of the ignition). I have a aftermarket radio that has its constant power coming from the bat location on the fuse box. My dash lights went out at some point, ended up being a bad fuse, replaced but may have not been the correct amps. problem fixed.
The Problem: With the key in the on position, the dash gauges are on the whole time regardless the headlight switch position with no dimming effect. The running lights up front along with the halos come on correctly, HOWEVER they will dim and will eventually turn off if the switch is twisted all the way (this only happens with the key in the on position and the engine not running)
With the engine running and lights on nothing dims. headlights, running lights, and gauge lights all stay on full blast. Then when i turned the key to the off position the engine keeps running. The engine turns off along with all lights when I push in the headlight switch to the off position.
With the key out of the car and the engine off (haha i know, sounds ridiculous). The dash lights will dim appropriately and the running lights will stay on full power as they should. However the brake light/ seat belt lights also dim and the tach needle moves up with decreasing brightness of the gauges and down to zero with increased brightness of the gauges.
I'm going to check all my grounds today and from there I have no idea where to turn. Thanks so much. Hopefully one of you can point me in the right direction.
Melting Slicks
Joined: Jan 2014
Posts: 2,478
Likes: 254
From: Downers Grove Illinois
I have a 1977 corvette thats having some issues.
Background: My GEN light was constantly on and eventually my battery stopped being charged from the alternator. Decided to go the easy route and get a 1 wire alternator. Problem solved. I recently installed halo lights up front that are tapped in with the running lights and work through a relay directly powered by the alternator. My low beams and high beams are also wired up through relays. On a 7 hour drive I stopped at a gas station and my engine wouldn't turn off (had the key out of the ignition). I have a aftermarket radio that has its constant power coming from the bat location on the fuse box. My dash lights went out at some point, ended up being a bad fuse, replaced but may have not been the correct amps. problem fixed.
The Problem: With the key in the on position, the dash gauges are on the whole time regardless the headlight switch position with no dimming effect. The running lights up front along with the halos come on correctly, HOWEVER they will dim and will eventually turn off if the switch is twisted all the way (this only happens with the key in the on position and the engine not running)
With the engine running and lights on nothing dims. headlights, running lights, and gauge lights all stay on full blast. Then when i turned the key to the off position the engine keeps running. The engine turns off along with all lights when I push in the headlight switch to the off position.
With the key out of the car and the engine off (haha i know, sounds ridiculous). The dash lights will dim appropriately and the running lights will stay on full power as they should. However the brake light/ seat belt lights also dim and the tach needle moves up with decreasing brightness of the gauges and down to zero with increased brightness of the gauges.
I'm going to check all my grounds today and from there I have no idea where to turn. Thanks so much. Hopefully one of you can point me in the right direction.
Background: My GEN light was constantly on and eventually my battery stopped being charged from the alternator. Decided to go the easy route and get a 1 wire alternator. Problem solved. I recently installed halo lights up front that are tapped in with the running lights and work through a relay directly powered by the alternator. My low beams and high beams are also wired up through relays. On a 7 hour drive I stopped at a gas station and my engine wouldn't turn off (had the key out of the ignition). I have a aftermarket radio that has its constant power coming from the bat location on the fuse box. My dash lights went out at some point, ended up being a bad fuse, replaced but may have not been the correct amps. problem fixed.
The Problem: With the key in the on position, the dash gauges are on the whole time regardless the headlight switch position with no dimming effect. The running lights up front along with the halos come on correctly, HOWEVER they will dim and will eventually turn off if the switch is twisted all the way (this only happens with the key in the on position and the engine not running)
With the engine running and lights on nothing dims. headlights, running lights, and gauge lights all stay on full blast. Then when i turned the key to the off position the engine keeps running. The engine turns off along with all lights when I push in the headlight switch to the off position.
With the key out of the car and the engine off (haha i know, sounds ridiculous). The dash lights will dim appropriately and the running lights will stay on full power as they should. However the brake light/ seat belt lights also dim and the tach needle moves up with decreasing brightness of the gauges and down to zero with increased brightness of the gauges.
I'm going to check all my grounds today and from there I have no idea where to turn. Thanks so much. Hopefully one of you can point me in the right direction.
Melting Slicks
Joined: May 2015
Posts: 2,365
Likes: 428
From: Cape Girardeau Missouri
Do you have schematics for your car? If so, check.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
7th Gear
Joined: Aug 2015
Posts: 7
Likes: 0
Do you have schematics for your car? If so, check.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
7th Gear
Joined: Aug 2015
Posts: 7
Likes: 0
Do you have schematics for your car? If so, check.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
Racer
Joined: Sep 2013
Posts: 361
Likes: 6
From: Jamestown Ohio
Strange Electrical Issues
This seems to be a common problem, mine is similar, but no problems with the lights, just constant power to the coil, with the key off, only 1.95 volts but enough to make the wire hot!, good thing I have a cut off switch.
New ign switch didn't fix anything either
New ign switch didn't fix anything either
2026 Loser of the Year
Joined: Sep 2013
Posts: 36,573
Likes: 7,015
From: New Or-leens Loo-z-anna
Members have always advised/warned me about two things:
Double-check harness ground wires.
Do not connect extra items to the Batt+ lug on the alternator
(you can do it....but why take the chance on an electrical problem)
As for the O.P.'s problems......disconnect one relay at a time/start the car/repeat disconnecting-starting the car until the problem goes away to find the culprit.
Double-check harness ground wires.
Do not connect extra items to the Batt+ lug on the alternator
(you can do it....but why take the chance on an electrical problem)
As for the O.P.'s problems......disconnect one relay at a time/start the car/repeat disconnecting-starting the car until the problem goes away to find the culprit.
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Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
if you disconnect the alternator wire while it is still running with the key off, what happens? does it turn off or keep running? you can isolate the 2 sides of the system and determine if it's the key or that one-wire alternator which by design is probably leaking enough current to back feed...at least that's where I'd start...
7th Gear
Joined: Aug 2015
Posts: 7
Likes: 0
Do you have schematics for your car? If so, check.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
7th Gear
Joined: Aug 2015
Posts: 7
Likes: 0
Do you have schematics for your car? If so, check.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
If '77 was the same as '79 the parking (running?) light circuit powers the dash lights circuit. A power lead comes from the "Park" fuse to the headlamp switch. When park or headlights are on it powers both the parking lights and the IP fuse via a splice at the "power" lug of the IP fuse inside the fuse box. It sounds to me like you are giving an additional +12V (either in "run" or "run+ignition") to the running light circuit.
