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Discussion Starter #1
I just finished a complete re-wire of my 70 Malibu Conv. I used origional factory harnesses, inside and out. The dash lights do not come on when I pull out the head lamp switch 1/2 way, or all the way out. I've checked the circuit wiring all the way down to the fuse block. It's dead at the fuse (small one at the bottom of the fuse block). Any ideas where I should go from there to track down the lack of power to this circuit? Everything else works just fine. Thanks, Steve
 

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If the fuse is indeed good, and you have rotated the headlight knob to give you full brightness and you have no power on either side of it (the fuse) with reference to ground...

Per my wiring manual, it looks like the 20 ga. dark green wire found in the plug that connects into the actual headlight switch is what gets 12 volts when you pull out the switch. Make sure the connector on the plug and on the actual switch corresponding with this wire is not bent, or broken. If that's okay, try another switch. if that doesn't do it, take a test light or voltmeter and stick one probe in this corresponding terminal and the other probe to a good metal ground. turn on the lights, if you get +12 at this wire, there is a break somewhere between this point and the dash lights themselves.

Joe

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[This message has been edited by Coppertop (edited 12-16-2000).]
 

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Discussion Starter #3
Thanks Joe, I've ordered a new headlamp switch, which should be arriving soon. (I wanted a new one anyway) If this doesn't cure it, well I'll punt. A question though. Am I correct in assuming that the primary power source for the entire lamp switch originates with the heavy red wire at the top of the switch- then power is distributed as required, when you pull out the switch ? As that switch is activated, does power go back to the fuse block for proper fuse protection to the lamps/tails/dash/etc. ? Thanks, Steve
 

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Steve

Are the tail lights working? The dash lights are connected to the tail light circuit. When the tail light fuse blows the dash lights go out.

Hope this helps
 

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Discussion Starter #5
No tails lights or front running lights either. But, the brake lights/ turn signals /headlights all work fine. Does that help in pinning this down ? Thanks Steve
 

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Discussion Starter #6
I should add that all fuses check out good, and all fuses, except the small one at the bottom of the block, light up my test light.
 

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Steve,

You are correct. The 12 ga. RED wire is +12 volts direct from the horn relay. It's hot all of the time, that's why (unfortunately) you can leave your lights on without the car running. When you pull out on the head light switch, the corresponding terminals on the switch get a 12 volt connection, go back into the fuse box for fuse protection and then out to the proper lamps. The only circuit that does NOT have a fuse is the headlights, they are protected by the headlight switch itself, which contains a bi-metallic breaker that trips and resets if a short were to develop between the switch and the headlights themselves.

Joe
 

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Steve,

THAT LITTLE ONE AT THE BOTTOM IS THE DASH/TAIL LIGHT FUSE!!!
 

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Discussion Starter #9
Coppertop, I know, but where would the problem lie if the fuse is good, but there's no test on either side of it. Is the headlamp switch itself the problem ? That's the only conclusion I have come to. Can you think of another ? By the way, Ive GOT to become a member here, and show you guys this car I bought. It's the perfect answer to a mid-life crisis. Thanks Steve
 

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Discussion Starter #11
Guys, I think I'm going backward with this wiring thing. New switch is installed. Every time I pull It out, the tail lamp fuse instantly blows. Still no dash lights either. I think I've royally goofed. I have checked for every possible loose wire, bad ground, the works. I think I have simply hooked the wrong thing to the wrong thing, but have no clue as to what it could be. HELP ! Respectfully, Steve
 

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UH-OH


Did it do this before with the old switch?? I'm asking as I been-there-done-that with replacement parts, the switch could be crap. Insist on Genuine AC/Delco.

Now back to the original problem...

Since your "tail lite" fuse blows, and since this is ALSO the fuse that protects the dash lights, there is a SHORT some where in the car, either in the dash light circuit, or the tail light circuit as they are "fed" from the stubby little fuse at the bottom of the fuse box.

Sooo... Try to do the easy part first, inspect the trunk wiring and brake light sockets for pinched wires against a metal ground. Then physically disconnect the wiring connector found in the trunk that feeds the rear bumper. Try the switch again, if it doesn't blow, the problem lies in the rear of the vehicle. If it DOES blow again, bad news, you have a short somewhere between the rear of the car and the dash or INSIDE the dash where power is fed to the dash lights. Fun ain't it


Other options include kerosene and a match, or park under a light pole and wait for lightning...

Keep us posted. (and hang in there, no one said it was easy to rewire a 30+ year old car.)


Joe
 

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Steve,

Yikes! I'm sorry I've got you chasing gremlins in the wrong places! Thanks to fellow team member Elree Colby, the tail lights are NOT on the "stubby" little dash light fuse--so get out of the trunk!

If the little fuse that feeds the dash lights is blowing right away when you pull out on the headlamp switch, you've got a short somewhere in the dash lighting circuitry.

Sooo, this could be a pinched wire grounding out, where? Well the stock radio's dial light wire could be the culprit, or the dash lights themselves, or the console lights if you have a console. Anything that has a bulb to illuminate it for night-time driving!

Joe
 

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Discussion Starter #14
Ok, message recieved. The fuse that is instantly blowing is the "tail lts" fuse, left side, 2nd from the bottom on the fuse block. The little stubby fuse at the very bottom of the block is hanging in there so far, but I'm not getting instrument lights. The switch I installed is an origional A/C Delco switch, checked by a reliable fellow whom restores dashes. I assume it to be good at this point. I'll start as you suggest, by pulling the plug to the rear of the car and see what happens. If it doesn't blow, I'll know there's a problem at the back side of the car. I may have two problems since the dash lights go through a different fuse (the little one). It doesn't blow, but the lights don't come on either. I have a test light and a nice volt/amp/ohm test box, so I'll hang in there with this. Can't take the Kerosene/match route, the damn car is just too nice. Even in the garage it looks like it's doing 90+ mph. If you have any other suggestions, lay em on me. Thanks ,Steve
 

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Discussion Starter #15
Well fellas, I'm back. I pulled the flat harness from the under-dash to isolate the rear of the car as the problem and BAM, the tail lite fuse blew instantly. So it's NOT the rear of the car. Then I pulled the turn signals and side running lites, and BAM the fuse blew again. I cannot, for the life of me, figure out this electrical gremlin. Maybe I'll just drive during the daytime. Steve
 

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Hook an ohm meter from the load side of fuse that is blowing and you will see it probably close to 0 ohms which is a short to ground. You can then start disconnecting one item at a time until you see the short go away. This will also save you a bushel basket of fuses!

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