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Old 05-25-2013, 03:53 PM
JD3426 JD3426 is offline
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Default cause of all lights going dim ?

I have a stock '72 Chevelle, 350 automatic with a console horshshoe shifter. Recently I noticed that all of the lights, dome, headlight, etc. go dim when I shift from park to drive or any other gear. I have replaced the voltage regulator with no change and am wondering about the neutral safety switch ? Any suggestions ?
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Old 05-25-2013, 05:04 PM
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I suspect the engine rpm's drop when you put it in gear. Original alts on these cars did not put out a lot of amps so slowing the engine done could very well be the cause.

Dim lights on these cars is pretty common at idle in gear.
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Old 05-25-2013, 07:08 PM
JD3426 JD3426 is offline
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I know what you are talking about with the low idle but this is clearly something different. It continues while driving and has just started recently.

I couldnt find anything here that sounded similar, other than the voltage regulator so I thought I'd ask.

Great site with lots of great info.
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Old 05-25-2013, 08:04 PM
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It could still be the alt. is going bad. Are there any other symptoms ?
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Old 05-25-2013, 08:19 PM
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Check all the ground connections...especially engine to body...
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Old 05-26-2013, 05:05 AM
JD3426 JD3426 is offline
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The ground at the battery (on the fender) was loose. Fixed that with no change. Other ground locations ?

The only other symptom is the shifter. I can shift out of park and see the lights dim and brighten, they will dim when going down the road also.

I did have a GEN light come on a while back but tightening the belt eliminated that.
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Old 05-26-2013, 07:25 AM
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Ground to fender handles everything except starter and ignition. The main ground cable from battery to engine handles those 2. AutoZone sells an electronic voltage regulator, direct replacement for the old mechanical one. They use to sell a Wells VR715 now it's sold with Duralast brand name, not sure of the new number but they can look it up.

I would start with checking your ground connections, battery connections then positive feed. Positive feed is from battery to starter. There is a main splice near the starter where positive splits off to feed the rest of the car.
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Old 05-26-2013, 07:56 AM
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Make sure the ground from the valve cover to firewall are intact. The ENGINE needs a good direct CHASSIS ground.
The Duralast P/N on the electronic voltage regulator is the same ...VR715
I use these on ALL my externally regulated Chevelles. The cover will interchange with the original so it will look completely stock.
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Old 05-26-2013, 09:31 AM
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I replaced the voltage regulator yeterday with no change. Will have to wait until tomorrow to check the rest of the suggestions. Thanks for the help.

I will have to double check but I dont remember any ground from valve cover to firewall ?
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Old 05-27-2013, 08:18 AM
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Bill, you don't need a ground from valve cover to firewall. They were originally installed only if the car was ordered with a radio. No radio, no straps. They were intended to suppress ignition electrical noise.

Engine is grounded by the main negative battery cable. Chassis is grounded by pigtail off negative cable to passenger side front fender. So engine and chassis are tied together at the negative battery post.

I bought a set of those straps years ago just to make it look original but never got around to installing them. Been driving the car for 9 years without them with no electrical issues. If installing them solves a problem then you need to keep looking. They're covering up the fact that you don't have a good ground from the battery to chassis or battery to engine.
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