Generator Light

Jan,

If it's been that way since you bought the car, then the charging system is keeping the battery charged.

Connect a volt meter to the battery and read the voltage. It should be ~12.4 volts. Start the car and read the voltage. It should be 14.2 to 14.6 volts.

The wire from the GEN light may have been disconnected during an alternator change or upgrade, and may be grounded somewhere in the car, probably in the engine bay.

John

quote:

Originally posted by jb1490:
Jan,

If it's been that way since you bought the car, then the charging system is keeping the battery charged.

Connect a volt meter to the battery and read the voltage. It should be ~12.4 volts. Start the car and read the voltage. It should be 14.2 to 14.6 volts.

The wire from the GEN light may have been disconnected during an alternator change or upgrade, and may be grounded somewhere in the car, probably in the engine bay.

John

Thanks for the tip. I was kinda thinking the same today and brought my volt meter with me to Cars & Coffee and popped the hood and it tested 13.95 at the battery when running. Plus to get into Cars & Coffee in the morning, you gots to go damn early, so I watched the dash lights when warming up the car in the driveway and noticed they got brighter as I revved the engine to wake the neighbors at 5:30...so I figured it is charging. I just noticed that light on my Group 4 also, so I will do the same and test it running.

Well on my DOES 200 Group 4, it does seem I am not getting charge. Before starting the car I have about 12.5 V testing at the battery, and then after running I am only at about 11.8 V with the car running. Then put da wife to work to measure the voltage while I reved the engine, but no improvement. I cleaned the terminals and wires at the battery too. Belts seemed a little slack too, so I tightened them at the alternator bolt adjustment, but no improvmement. Any suggestions for further testing? I turned on the AC, radio and lights too and watched the amp meeter on the car dash and it was in the negative and reved the engine but no movement toward positive.

A very important part of the charging system is the little bulb for the "charge" light in the speedometer. This bulb provides a resistance element for the voltage regulator. As a redundant resistive element, there is a large resistor in parallel with the wiring at the bulb socket. If your wiring has been fiddled with, this resistor may be missing, and the bulb may be burnt out or loose.

The other element is the voltage regulator, which is very cheap and easy to replace.

Jan,

Does the charge indicator light in the speedometer of your Group 4 car illuminate when the key is turned on?

If a one wire alternator has been installed, then the charge indicator light wiring is not needed, unless the alternator has been modified for use with a warning light.

John

Thanks Dave. So with only 11.8 volt at the battery terminals with the car running and the generator light showing on the speedo, you think it could be the voltage regulator? I was just going to change out the alternator unless there is some other test I can do. I suppose to find the voltage regulator I just follow the wires from the alternator. Maybe I need to dig out the engines for dummies book and see what else to test.

John, I just turned the key to the on position and the generator light on the speedo does not light up. But start the car and it does light up.

Plus, this amp meter on the top right dash goes a few degrees into the negative range when I run AC, lights, etc., but I believe before that needle used to kick into the positive range when I was driving.

Jan,

The colors of the two smaller wires look correct (and in the correct locations) for a stock type alternator with a remote mounted voltage regulator. The regulator was originally mounted on the firewall, to the right of the engine.

John

quote:

Originally posted by DOES 200:
.....you think it could be the voltage regulator? I was just going to change out the alternator unless there is some other test I can do. I suppose to find the voltage regulator I just follow the wires from the alternator. Maybe I need to dig out the engines for dummies book and see what else to test.

John, I just turned the key to the on position and the generator light on the speedo does not light up. But start the car and it does light up.

Sounds like your charge light works OK. A voltage regulator change would be the first thing to do. $15 bucks at Pep Boys. They look like the picture below. Located on the right side firewall. Look for it from underneath the car.

Thanks guys. Is there a particular number that identifies that voltage regulator when I go to get the part? I was at Kragen today asking about an alternator and they insist on knowing what car it is, although I tell them to look up the 351 clevland, But no, they need to know the car so I says Pantera and of course "whats that, its not in our system"

Jan,

Try '71 Mustang.

John

Damn that was easy to take out. Now just need to get another and give it a try. Nice to have a small digital camera, not more marking wires where they go, etc.

I have an extra one if you need it. Worked fine when I removed it...

quote:

Originally posted by Z06 Pantera:
I have an extra one if you need it. Worked fine when I removed it...

Thanks, but just returned from getting one. Then if this isn't the problem, then I will have an extra one too. Can't change it and start the car tonight though as it would wake the dead.

Thanks for all the help. What an easiest fix ever, swaped the old regulator for new and bada bing bada boom, freakin thing charged like a champ. Put da wife to work on the voltage meeter at the battery terminals while I reved the engine some and now got 14+ at the battery. Amp meeter on the dash danced way in the positive too, and no more lit gernator light on the speedo. Now to put back all the bulkhead that I took apart thinking I was going to change the alternator.