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Discussion Starter #1
Any one have any ideas as to why the Gen light would be on at idle & low rpm? The alternator has been change to a internal regulator & seems to be working fine. I also noticed that when driving at night, the lights begin to flicker (just enough to notice) & the turn signals will flash just a bit slower when the Gen light begins to become visible. I'm not sure what to check first. I have 13+ volts while the engine is idiling.


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Jim Grimes
1970 Malibu
Member# 407 ACES Member# 3774
"The only substitute for cubic inches is MORE CUBIC INCHES!!"
 

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How low is your idle set???

At 1000 RPMs your voltage at the battery terminals should be at least 13.8 volts. If not, your charging system is not up to par.

Dimming is normal, as most alternators don't "kick" till about 1000 rpms or so, but flickering sounds like a problem is a-brewing.

Joe

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Discussion Starter #3
Joe,
The lights will begin to flicker (get dimmer) at about 1500 rpm. The car idles at about 850 rpm. Do not have the tach installed yet, so I can't give exact numbers. I have been driving the car for over a week back & forth to work with no other problems. Just concerned about the Gen light being on. Is it possibly a grounding problem? I had the car running before I had any of the front end sheet metal hung & had ground wires just hanging in mid air, & the light was not on then. It started after I put the front end together. Seems strange to me.

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Jim Grimes
1970 Malibu
Member# 407 ACES Member# 3774
"The only substitute for cubic inches is MORE CUBIC INCHES!!"
 

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If they are flickering at 1500 rpms, that what I would consider unacceptable--especially for an "updated" charging system.

Is the battery in reasonably good condition?

Yes, first check your grounds, especially make sure the actual alternator is tight to the bracket and the bracket is tight to the engine block, as this is how the alternator sees its ground.

You should also have a wire (about 12 ga.) coming off ot the (-) battery terminal and gets bolted to the passenger side fender. This ensures you have a body ground.

After that has been checked, get a voltage reading as I described originally. At 1000 rpms, if you don't see at least 13.8 volts, there's a problem with that alternator.

Joe



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Creator of Team Chevelle's RADIO TECH for original audio questions and answers


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Discussion Starter #5
The battery is suspect. It was in the car when i got it, over a year ago & it sat i the garage for 6+ months. But, I have only had a problem starting the car 1 time after I had it reasonably ready to run. Like I said, I have not had a problem with it going back & forth to work. (only 3 miles each way) I have the ground from the battery connected to the inner fender. Is this acceptable, or should it be to the fender it self?
I will have to get an accurate voltage reading for you next week & let you know what it is doing at idle & above. Thanks for the help

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Jim Grimes
1970 Malibu
TC# 407(Gold), ACES # 3774
"The only substitute for cubic inches is MORE CUBIC INCHES!!"
 

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Discussion Starter #6
Joe,

I think I found the problem by accident. I checked everything that you suggested & found that it was overcharging. I called the store that I got the alternator from & they said to bring it in & they would exchange it. So I did & still had the same results. I was also trying to get the horn to work & found the horn relay was no good. Replaced the relay & now the horn works and no more problem with the lights flickering or the Gen light being on. It seems that the horn relay was the problem. Go figure!
Thanks again for the help.

Jim
 

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Gramps;

It may not really be the horn relay it's self, but the connections that are made there.

Normally, the alternator output line goes to the horn relay and then to the battery and car circuits. It serves as a junction block. If the connection wasn't too good, that may have been your problem.

Just for fun (and to learn a little), you could put the old relay back in and see if the problem is still gone. At that point, you would know that the alternator light problem was with the connections and not the relay. (this assumes that the problem wasn't "fixed" while doing something else at the same time, and you didn't notice it)

I sure hope it's solved.

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Wes. Vann
Technical Reference section
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Discussion Starter #8
Wes, I had the relay off & cleaned the connections & the radiator support where the relay bolts up to see if that was the problem with the horn. It's possible that it could have been a bad connection, but I don't think so. I also have the car converted to the internal regulator alternator. I will try putting the old relay back in & see, if I can find it. I'll let you know if it was the relay.



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Jim Grimes
1970 Malibu
TC# 407(Gold), ACES # 3774
"The only substitute for cubic inches is MORE CUBIC INCHES!!"
 
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