Hello everyone,

I have just joined the group. I just bought a 69 Z28 re-creation. It has a 350 cid with an M21 tranny. The "GEN" light is on in the dash. There is a volt gauge on it also. Can anyone give me some info on what might be the issue? I took the alternator to a parts store and it checks out good. Charging at 15.6 volts under a load. I know the alt is good. The volt reg looks brand new. Any info on this would help. Take care and thanks.

There is a batt wire from the voltage reg to the alt that is only hot when you are cranking the starter with the key. It's refered to the ignitor or excitor wire. It send the signal to tell the alt to start charging. If all the alt checked out it's most likely the wire it self or the voltage reg failing...

I checked out the wire. It has good continuity and with the key in the run position there is good voltage there. I will get a new volt reg and put it on. The plug that goes into he volt reg is fine. What is the other wire coming off the volt reg go to. I cannot find it in any schematic. Does the horn relay come into to play with the charging system. I heard that the Wells volt reg VR715 is a good volt reg to convert to. Do you suggest that? If so, how do you hook it up? Thanks

There should be four wires in the VR plug as designed. There is also a ground wire from the case to radiator support - don't forget to hook it up - it puts the alt case and VR chassis on the same reference point.
Yes, a Wells VR715 reg is Plug & Play, nothing more is needed.

Color of wire in question?

According to other posts. Since the volt reg is mounted directly to the rad support. There is no need for a ground wire. The extra wire is pink with black stripe. I traced it from the volt reg to the fire wall junction box and then into the the wire connector going to the ignition switch. Which wires do you plug into the VR715 volt reg? I think I will go that way. Thanks. I tried to attach a picture of my current volt reg but don't know how to do that. Thanks

Ahh, the famous disconnected key buzzer wire - pink w/black stripe - goes to the horn relay - center spade terminal between the buss bar and blue wire and green wire.

ahh, the famous disconnected key buzzer wire - pink w/black stripe - goes to the horn relay - center spade terminal between the buss bar and blue wire and green wire. ditto that..

Thanks for the info. Since that was plugged into the volt reg, would that cause the alternator to not charge or cause the gen like to come on?

Sounds like your alternator is definately charging. In fact, 15.6 is a bit on the high side.

As Dave states, 15.6 volts is too high. But, where and with what are you using to measure? Using a digital multimeter? Don't use an aftermarket add-on voltmeter.

Charging voltage is measured across the battery posts after running the engine at 1500-2000 rpm for 10-15 minutes - allows the battery to get recharged and temperatures to stabilize, both for the battery and the VR.

With no accessories on, just ignition, the max voltage should be 14.6 volts with maybe initial start up spikes of 14.8 volts.
With lights on, blower on high speed, and wipers on, min voltage might be around 13.2 volts. As a FYI, lower engine rpm and voltage will drop, then battery starts to give current to keep accessories running. Speed up rpm, alternator develops enough current to 'handle' the load including recharging the battery.

So regulator may be set incorrectly if it is a mechanical reg. Plugging in a VR715 will help cure it. The mechanical reg can be adjusted, but one needs to know the temperature of battery electrolyte and regulator, and a known load, usually a 1/4 ohm 250 watt rheostat, to set the reg. Its easier just to replace with an electronic reg.

I have purchased the VR715 and a new horn relay. I hope that this cures the charging problem. Thanks for the info. I am pulling the engine and tranny. I will put the new parts on once i put everything back in.