36-120 Voltage Question

Posted by wren0915 On 2020/3/16 16:27:15

Hi everyone, I've been a reader for a while, and decided it's time to join. I have a 1936 120B Sedan, and recently i had to replace the regulator. Apparently the generator was good, but nothing was coming out of the regulator. This made sense as every few weeks I'd have to recharge the battery. I'm not the best at electrical stuff, especially on this car, so I wanted to come to the experts.

The voltages I'm seeing off the battery and reg seem odd. It is an Autolite 6V positive ground system. Battery is an Optima. Here's what I'm seeing:

Battery with power off: 6.2V
Battery with Car running, positive meter lead on positive terminal: approx 10.5v (this was consistent through all tests)
Battery with car running, negative meter lead on positive terminal: -2.0v
Battery with car running, negative meter lead on positive terminal, headlights on: -5.0v

Regulator wire with positive meter lead on ground: jumping all over (same with lights on or off)
Regulator wire with positive meter lead on the wire, headlights off: .03
Regulator wire with positive meter lead on the wire, headlights on: -.5

I don't know if I need to repolarize, or if that has anything to do with the numbers, but everything I'm ready says these are way too high.

The 5a fuse in the regulator is not blowing either.

Any thoughts?