not model A/ Wireing

[jhowes]

I hope some of you old car guys will know the answer here. I have a 1937 Chevy truck and it has a wire-wound resistor connected to the light switch. Why? It has one end hooked to ground and the other end can be grounded by a relay contact (or so it appears). Otherwise the other end goes to the generator. It is called the "light switch resistor" on the circuit diagram in the manual. The 37 trucks had no voltage regulator, just a cutout. Thanks in advance. Jack

[Kurt in NJ]

It changes the charging rate, cuts in the resistance to reduce the charging rate when the lights are off

[Gunmetal blue2]

A lot of those were 8 volt batterys with 6 volt lights.

[BILL WILLIAMSON]

Bought a '32 Coupe with 2 1/2 MILES of RAT NEST wiring!! Wired it "MY" way, with only about 60' of wire!---ALL one COLOR---LOL
Bill Simple

[J Franklin]

I don't think any car came with an eight volt system from the factory.

[jhowes]

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I think post 2 is correct, but does the light switch cut out the resistor.?

[100IH]

Many old tractors had resistors in the light switch to manually give a low or high charge rate.

[Tom Wesenberg]

What Kurt said in #2. When the lights aren't on, the field windings current will pass through the resistor, and this will lower the field windings voltage and magnetic field strength that the armature spins in. This will lower the charge rate.