JD 400 Voltage Regulator Questions

[Cdnturboz]

I have a 74 JD 400 and have a quick question on the voltage regulator.

Long story but redid the entire motor, put everything back in/connected dash etc. blew all the bulbs on the sled. Figured possible faulty voltage regulator so I found a NOS Kimpex one on eBay and installed it. Lights blew again - my question is, does anyone have a photo of where the voltage regulator wires plug into?

The Kimpex one looks factory, has two wires, the one is brown and has a ring terminal for ground , and the yellow one according to the wiring diagram is supposed to go into the harness plug. Problem is I can’t remember which harness plug it goes to.

Any help would be great.

[400brian]

The V-reg plugs into a coupler that is spliced into the same wire that feeds the tach. The wires that feed the tach are a yellow wire that feeds the tach bulb. Then there is a brown and a brown / White wire, one of those two should have the plastic plug spliced in to go to the V-reg.


If you had a bad connection between the lighting coil and the tach, the V-reg wouldn't be getting the current to regulate ( Just a thought ). Obviously you have to have a good ground at the v-reg.

Do you have electric start on this?

[Cdnturboz]

No electric start - you’re talking the lone brown wire/black connector on the left? (in the photo)

[400brian]

I could be wrong, I'm no electrical engineer, but functionally, I don't think it really matters where the V-reg is connected, as long as it is a hot wire in the loop with the lighting coil. But I believe the V-reg does plug into that brown wire.

[Cdnturboz]

Thanks I’ll give it a try

[Cdnturboz]

Update - it was indeed the lone brown wire. Thanks again

[400brian]

Love it when a plan comes together!

[AirborneX4Special]

https://duckduckgo.com/?q=love+it+when+ ... PQlXNH36mI