New alternator, 4 regulators, still can't find voltage draw

[ggucci3]

1973 chev g10, just replaced the alternator and regulator again. There is a current draw somewhere in the charging system, just cannot find where. The system charges at 17-18volts, so i'm burning through regulators. key off, the battery shows 4 amps draw; when I disconnected the regulator, the draw goes to 0. Any ideas??

[SS Tim]

A 73 G10? As in van?
Suggest posting this in the electrical forum and reviewimg the existing wiring against the factory manual's schematic.

[Andy4639]

Originally Posted by ggucci3

1973 chev g10, just replaced the alternator and regulator again. There is a current draw somewhere in the charging system, just cannot find where. The system charges at 17-18volts, so i'm burning through regulators. key off, the battery shows 4 amps draw; when I disconnected the regulator, the draw goes to 0. Any ideas??

17-18 volts are you sure. That should be enough to pop bulbs and kill just about everything in the truck.
Have you tried taking the negative battery cable loose and putting your test light clipped to the cable and to the battery. Then start pulling fuses one at a time until the light goes out. This will tell you what circuit the draw is.

[VetteVet]

Originally Posted by ggucci3

1973 chev g10, just replaced the alternator and regulator again. There is a current draw somewhere in the charging system, just cannot find where. The system charges at 17-18volts, so i'm burning through regulators. key off, the battery shows 4 amps draw; when I disconnected the regulator, the draw goes to 0. Any ideas??

Four amps is a lot of draw with the key off. If you unplug your regulator and the draw goes away it would seem that the draw is in the regulator. Have you disconnected the alternator plug and the large wire on the bAT stud while leaving the regulator plugged in?

you are throwing the alternator into full output with 17 to 18 volts and a four amp draw would not do that. It suggests to me that the regulator or the alternator plug is wired wrong.

The regulator should be wired as follows.
F -blue
2- white
3- red
4- brown

The alternator is wired.

R- white
F- blue

Having the blue and white wires switched would create a draw and it might throw the alternator into full charge.

Do you have a battery gauge in the truck or a charging light and how are you determining the four amp draw and the voltage output? I assume with a multi-meter.

This is the way the 72 wiring shows. The factory converted to the internally regulated alternator in 75 which is doable on the older vehicles as well. This might be your best bet if you can't find the draw.

[starterman99]

A 1973 should be internally regulated 10si. Do you have an external regulator? all my application catalogs list 1973 as internally regulated alternator. when you got the new alternator did it look exactly like the original and hook up the same way or was the two wire plug different?