Wiring Gremlin - 67 Plain Jane - Team Camaro Tech
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post #1 of 12 (permalink) Old Nov 25th, 11, 04:18 PM Thread Starter
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Wiring Gremlin - 67 Plain Jane

First off, let me state that I have done a search through the forums and there are a few posts that are sort of like my issue, but not quite the same. Lately when I have driven the car I have noticed that the GEN light is very dimly lit all the time. If I put on the emergency brake or if I engage the back-up light circuit, the GEN light comes on bright. With the ignition switch turned on, but the engine not running - if I put the car in reverse the GEN light is on bright, but the backup lights are not lit.

I took the car to a local garage that is usually pretty good with old muscle cars and they tested the battery and alternator - both tested fine. They claimed the voltage regulator was bad. They replaced it, but I still have the same issue. The only thing I have done to the car lately is to remove the heater box to repair a leaking heater core. I have looked at all the wiring near the heater box or the heater controls behind the dash and I don't see anything out of place.

All of the other electrical circuits in the car seem fine - dash lights, dome light, headlights, parking lights, brake lights, blower motor, turn signals, hazard lights, trunk light all work fine and do not cause the GEN light to glow brighter when turned on. The issue seems to be related to the e-brake and backup lights only.

Any suggestions?

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post #2 of 12 (permalink) Old Nov 25th, 11, 05:13 PM
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Re: Wiring Gremlin - 67 Plain Jane

Normal condition is GEN light on when alternator is not running.
However, with parking brake set, GEN light should not be on, BRAKE light should be on.
Both bulbs, as well as fuel gauge, OIL light, and TEMP light, get power from ign sw via pink wire from fuse panel.
Other side of BRAKE light bulb is tan wire to switch at pedal. Switch at pedal places a ground at the pedal switch.
Back-up lights, light green, get power from fuse panel and from Ign switch, pink wire.

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post #3 of 12 (permalink) Old Nov 25th, 11, 08:30 PM
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Re: Wiring Gremlin - 67 Plain Jane

hey mark,
I joined this forum with the hopes of finding someone with a topic related to an electrical issue I have with my 69.
similar to your condition, with my ignition in the on position, all the idiot lights illuminate like they are suppose to, but when the key goes to the on position, my "gen" light remains on, sometimes dim, sometimes normal intensity. The altenator, voltage regulator and horn relay have all been found to be in proper working order, and the battery is maintaining it's proper voltage as well. All fuses are good as are all the electrical connections that I can see. Everything else about the car electrically functions normallly. I had a similar issue with my 67 years ago, so when I was having it painted, I simply removed the entire electrical system, un-taped it all, replaced any worn or spliced wires, re-taped the harness and re-installed. havn't had a problem with it since (20 yrs)...as I am in the process of painting the 69 right now, it looks as though I may have to do the same thing again. Unless I just get lucky, and happen across the responsible wire or circuit, it will be faster to just refurbish the wire harness like I did before...
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post #4 of 12 (permalink) Old Nov 25th, 11, 09:02 PM
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Re: Wiring Gremlin - 67 Plain Jane

Check the Voltage Regulator ground to the radiator support. I think in 67's they used rubber feet on the regulator so they grounded the unit with a strap. 69's are mounted direct to the support so check there. Also check the dashboard grounds for both years.


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post #5 of 12 (permalink) Old Nov 25th, 11, 09:15 PM
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Re: Wiring Gremlin - 67 Plain Jane

That sounds familiar but it’s been so long I don’t remember if it was the common top center instrument cluster grounding screw, a bulb contact on the back of the cluster, or the brake light switch on the side of the emergency housing. Pulling the dash harness out and repairing any of the splices and burned wires was something I always use to do also because even after 20 years, someone always had hacked up the wires for an 8 track, aftermarket gauges, or switches for who knows what… Oh, I’ve also had trouble with the contacts on the back of the dimmer switch shorting out from dirk and water corroding the contacts on the back and the plug melting from using halogen headlights that pulled more current.

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post #6 of 12 (permalink) Old Nov 25th, 11, 09:57 PM
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Re: Wiring Gremlin - 67 Plain Jane

I think it's a connection problem between the voltage regulator and the dash light bulb. The gen light works by having voltage on both sides sort of. With the key on engine off ignition voltage is supplied to gen bulb thru pink wire and the other wire finds a ground in alternator or regulator. (not sure which cuz I'm old). Once the alternator is turning (engine running) and producing current it puts voltage on the wire on gen bulb opposite the pink wire. With proper voltage applied to both sides of the bulb the light goes out. What I think you have is not enough voltage coming back from voltage regulator to turn it off completely. This is a very common problem on cars with internal regulated alternators.

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post #7 of 12 (permalink) Old Nov 26th, 11, 08:02 AM Thread Starter
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Re: Wiring Gremlin - 67 Plain Jane

Quote:
Originally Posted by Everett#2390 View Post
Normal condition is GEN light on when alternator is not running.
However, with parking brake set, GEN light should not be on, BRAKE light should be on.
Both bulbs, as well as fuel gauge, OIL light, and TEMP light, get power from ign sw via pink wire from fuse panel.
Other side of BRAKE light bulb is tan wire to switch at pedal. Switch at pedal places a ground at the pedal switch.
Back-up lights, light green, get power from fuse panel and from Ign switch, pink wire.
You may have to talk to me like I'm the village idiot, because in this case I feel like that's what I am. I'm not much of an electrical guy, but I do think I understand the most basic principals. I just came back in from messing around with it some more and I did notice that when I put on the e-brake, the brake light comes on - only very faintly. I had been focusing on the bright GEN light. Could the problem be at the fuse panel?

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post #8 of 12 (permalink) Old Nov 26th, 11, 08:08 AM Thread Starter
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Re: Wiring Gremlin - 67 Plain Jane

Quote:
Originally Posted by 69-Pace View Post
Check the Voltage Regulator ground to the radiator support. I think in 67's they used rubber feet on the regulator so they grounded the unit with a strap. 69's are mounted direct to the support so check there. Also check the dashboard grounds for both years.
Brian, you are correct - the voltage regulator is mounted with rubber feet. I disconnected the ground wire that runs from the voltage regulator to the radiator support, cleaned off all of the contact surfaces and reattached the ground wire. No difference. I'll have to take a look at the dashboard grounds, although it seems like if the problem was in there I would be having problems with the dash lights, etc. I have to prep myself for becoming pretzel man to climb under the dash. My back is still angry at me for doing that yesterday.

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post #9 of 12 (permalink) Old Nov 26th, 11, 08:27 AM
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Re: Wiring Gremlin - 67 Plain Jane

With the faint brake light, problem could be a rusty ground, read high resistance, at the pedal switch to reduced battery voltage from the battery and would include the fuse panel.

I would check the pedal switch ensuring a good ground.
The next step I would do is disconnect the battery and follow through the red wire pigtail to the fuse panel and clean all the connections, ie, junction block, horn relay buss bar, with wire brush and reconnect. This will ensure good battery voltage to the inside of the dash. Grounds are important, they need just as much attention as supply side.

However, brightness of the dash bulbs depends on the charge of the battery itself.
GEN light gets one side of power from the ign switch,
The other side of the bulb gets power from the VR#4 terminal when alt is running, field relay is closed inside the VR and applies power to the other side of the bulb and light goes out due to having battery voltage on both sides.
Old school symptom was a dimly lit GEN light indicating a heavy charge to the battery or a heavy load on the electrical system and a normal condition.

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post #10 of 12 (permalink) Old Nov 26th, 11, 09:52 AM
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Re: Wiring Gremlin - 67 Plain Jane

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post #11 of 12 (permalink) Old Nov 26th, 11, 10:22 AM
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Re: Wiring Gremlin - 67 Plain Jane

Check all your fuses.

I had the same condition and found a fuse burned out. Don't remember which fuse but when I changed it the GEN light issues went away.

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post #12 of 12 (permalink) Old Apr 28th, 12, 07:46 PM Thread Starter
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Re: Wiring Gremlin - 67 Plain Jane

Quote:
Originally Posted by Vega$69 View Post
Check all your fuses.

I had the same condition and found a fuse burned out. Don't remember which fuse but when I changed it the GEN light issues went away.
Bingo! That was exactly the problem!! The fuse for the backup lights was blown. As soon as I replaced the fuse the issue went away. Very strange symptoms for such an easy fix. Thanks for the suggestion - problem solved.

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