i would like to get rid of the idiot light for the charging system and install a gauge.my system has the external 4 wire regulator.can i run ign 12v to the brown wire that goes to the light and have the system work? thanks for any input

You can install a voltage gauge that picks up switched power from under the dash, but not from the voltage regulator brown wire. The voltage gauge will measure voltage difference between the posts, but not allow enough current through to energize the alternator through the brown wire.

One idea is you could paint the idiot light bulb black or cover it with electrical tape, but keep it in place so it can allow the alternator to receive voltage through the bulb.

Just keep the idiot light and wire the volt gauge to a switched source. The easiest place is at the IGN terminal at fuse box. (see pic) The brown wire is actually the ground wire for the idiot light (goes to terminal 4 at VR) The bulb (and a bypass resistor wire acts as a current limiter.

http://www.chevelles.com/showroom/data/500/DSC00923.JPG

thanks i will give it a try

Just keep the idiot light and wire the volt gauge to a switched source. The easiest place is at the IGN terminal at fuse box. (see pic) The brown wire is actually the ground wire for the idiot light (goes to terminal 4 at VR) The bulb (and a bypass resistor wire acts as a current limiter.



So if you want the idiot light to stay off, do you just not put this to ground?? I also put an OE type gauge in and don't know what to do with the brown wire..

So if you want the idiot light to stay off, do you just not put this to ground?? I also put an OE type gauge in and don't know what to do with the brown wire..

That will just make the light stay on. Try removing the bulb and check the charging system to see if it is still charging. If it is, the bypass wire is still intact and working. If not, you can either leave bulb in, or bypass bulb and put a 35 ohm or so resistor in its place.

What year???

Anyhoo, if you don't want an idiot light, just remove the bulb, or cut each wire leading to it and tape them up carefully. GM designed the circuit carefully, so if the bulb would fail, you would still have a charging system that operates. The bulb parallels a resistance wire anyhow, so it doesn't matter if the bulb is there or not. Don't ground any wires.

IF using a voltmeter, simply connect the (-) side of it to a good metal ground, and the (+) side of it to the IGN (ignition) terminal of the fuse box. This way it will be switched off when the car is not running and give you a good idea of the system voltage seen at the fuse box.