The Stovebolt Site Forums The Shop Area The Electrical Bay alternator for 51 GMC 228 engine

Cletis,

This is ancient history, but relevant to some recent alternator posts. Your schematic does show the idiot light and you can see how it works in the circuit. The filament in the "gen" light, the resistance wire in this line, or the ever present diode all serve the same purpose, which is to limit current to the alternator after start up, and to limit the amount of voltage that is allowed to flow back to the ignition switch when the engine is shut down.

I guess the conclusion would be, if you don't have a dash light, you use a diode. If you WANT a dash light, you can rig one up INSTEAD of a diode. I don't know what value the lamp would be, but it would be small as not to pass much current through its filament.

So much for old posts...I was stoked because I opened the wiring diagram in the link you provided, and after MUCH searching, traced the alternator #1 through the little light and into the ignition switch. Nuff said!

Stuart

Hi Alan,

What is the function of the #2 terminal block?

52Ted

Hey, 52Ted

It's just to allow for more connections. Simple as that.

Those terminals supply a full 14 volts to whatever I hook up to them -- and that includes my fuse box which originally had a smaller and much longer wire bringing power to it, which meant less voltage.

If you make that modification to your truck, you will see and feel a difference.

I'll tell you what also made a real noticible difference, too, was using a fusible link on my electric fan instead of a circuit breaker! All the info is at my site.