VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1931 generator and voltage regulator wiring

I am just going to start my 194 engine after rebuild. The wire's in my 1931 1/2 ton were quite gone from years of sitting and rodents, could someone help me figure out the wiring from generator and voltage regulator I have the circuit breaker mounted onto the generator one wire comes out of generator housing attached to breaker which leaves the opposite terminal open, where does this terminal connect to Secondly I have 5 terminals on the voltage regulator I have identified the battery terminal, the dim terminal and the head terminal that go down to floor dimmer switch These terminals are stamped S. The other two remaining terminals are stamped H and i do not know where the wire leads correspond to. I will buy a wire harness later, i want to get engine started and checked out before i put he body, fenders, etc back on. But I want to check and make sure starter, generator, coil, and voltage regulator are all working

Barker has a nice page of info just for 1931 Chevrolets
1931 Chevrolet Scroll down to Wiring Diagrams

The Old Car Manual Project has some as well
WIRING DIAGRAMS FOR CHEVROLETS 1923 - 1960

The 1931 had a circuit breaker mounted on the generator and did not have a voltage regulator?????
A voltage regulator has a circuit breaker built in to it.
Something is wrong here.

what I am describing looks to me like a voltage regulator, i will describe further It is mounted on firewall It has a black cover about 3x3 inches it has 20 amp fuses on either side, this is where the battery connection terminal is. Inside are two relays , it is the terminals of these relays i am trying to identifu. Was this considered the fuse block terminal

What ever it is it is not "factory"
Posible head light relay for low and high beams due to the pair of relays. in one box.

I belive you are correct I traced one of the terminals going to the dim terminal on the floor mounted headlight dimmer switch and another terminal went to terminal marked head on the floor mount dimmer switch.
It definitely sounds like what you have described
Thank You

The generator for your 1931 should be a Delco-Remy Model 943J. There is a cutout that sits on top of the generator and the cutout has only two terminals. The wire coming out of the generator goes directly to the GEN terminal on the cutout. The BATT terminal on the opposite side of the cutout goes to the back of the amp meter. A voltage regulator was not used on the 1931 Chevrolet.

In order to run the engine and test the other components it will be necessary to either make up test wiring or buy a new harness and only use some of the wires.

To make up test wiring: A battery cable goes from the positive battery post to the starter switch. A wire goes from the starter switch to the ammeter. The negative battery cable goes to either the frame or better yet to a bolt on the transmission.

Two wires from the other post on the ammeter, one to the "bat" terminal on the generator cutout, the other to a switch (can be ignition switch, toggle switch, alligator clip) and then to the positive post on the coil. A wire from the negative post on the coil to the points inside the distributor (probably need a temporary stud or screw insulated from the distributor body.

That temporary wiring will allow you to start the engine, shut if off with the switch (alligator clip?) and see if the generator is working. You probably have to polarize the generator by touching the "gen" with a wire from the positive battery post (or the wire from the ammeter that you will put on the "bat" terminal). All you need is a quick touch. If you hold the wire on the "gen" terminal too long it will fry the ammeter.

I am thinking that what you are calling the "voltage regulator" is actually the light switch. It has a fuse on the back (where all the screw on terminals are located. The fuse connects the wire from the ammeter to the body of the switch. There are several positions around the switch that connect to the headlights (through the dimmer switch), parking lights, horn, taillight, wire to brake light switch, etc.