MT 372 dummy lights

[Ilikeurtractor]

I don't have a lot of experience with removing terminals but they usually have a clip that needs to be collapsed in order to remove them. Use a dental tool or maybe a pin to release it while pulling the terminal if that's the type it is.

 

[shags-72]

Ok got the new regulator in. plugged it in and 14.1 or so volts. Sounds good. Lights work correctly. Then a small whiff of smoke from around the regulator. The resistors on the bottom are getting hot. Not sure how normal this is.

 

[Ilikeurtractor]

Hmmm. . That's probably not good. You might want to invest in a clamp type DC ammeter and see if any lines are pulling high amps. Make sure your battery is in good shape. You may have damaged it if you are still using the same one.

 

[shags-72]

Well I just went through the wiring which is kinda crazy because the new regulators wire routin in it is different than the original and it came up the same as the original. I put the original back in and 14.3v! But the dummy light comes on when key is off like before. The new one didn't do that. Is the regulator supposed to be isolated from ground? The original had grommets molded on and the new one doesn't.

 

[Ilikeurtractor]

You must have had a loose connection the first time around. The case should be grounded but the "E" line is ground so that should be providing it although I don't see a wire from it for the regulator in the diagram. Some of my regulators have rubber grommets and some don't. They may be for vibration isolation.

It sure seems like the A and N lines are swapped based on what you were reporting. I'm away from mine so I won't be able to check until next week. Maybe my diagram is wrong but I do know the N wire is used for the charge light so there should be 23 ohms on that one to the case of the regulator.

 

[Ilikeurtractor]

I confirmed the N line should be between 20-25 ohms to ground. The A line is open until you pull in the light solenoid. This was tested on two different regulators.

 

[shags-72]

Sorry to have fallen off the face of the earth but the boy had a starter go out on his car and it was very strange. Not a sound or anything so I thought it was a neutral safety or ignition, but when hit with a hammer it started verifying the starter. Usually get a click or something out of the area. I checked mine and I get the same. The new one is more at 44 ohm and the A is open until the coil is made. I get 100 ohms though when I do that on the old one and 27 with the new one.

 

[Ilikeurtractor]

The above conflicts with your prior statement below unless I'm misunderstanding you.

I am checking the white wire which in my diagram is N and it shows no continuity, but if I close the coil again it is 100+.

 

[Ilikeurtractor]

Some final notes on these mechanical regulators for people needing to change out the solenoids. You can, and I have, replaced the light solenoid with a standard 12V solenoid coil. Technically, this coil should be more of 6V coil solenoid because it operates at half the nominal system voltage off the N wire. The other coil (field solenoid) will be more sensitive to proper selection. A standard coil could be used as a direct replacement, but what currently occupies the 10 ohm place in the circuit will need to replaced (or added to) with a value which brings the solenoid coil resistance to a value which causes the charge out put to be within spec. A potentiometer would be the best as this will allow some adjustment of the charge voltage to obtain around 14-14.5V.

 

[shags-72]

You know I didn't even check the wire color or position. I just tested the one you had checked in the picture. LOL. Who knows. I ended up putting the new regulator on and ran it today mowing for almost 2 hours and no problems yet! I am not getting rid of the old one though. I want to thank you for putting your time in helping me out. People like you make the world nice. Hopefully the new regulator fixes everything and I won't have to come back and bug you some more. Thanks again!

 

[Ilikeurtractor]

Glad it is working for you. Happy tractoring

 

[EBGwd59]

well I guess I will have a spare regulator. The light would come on when the key got turned on and went off when the engine started. It did come back on when the key was turned to off with the engine running. Could it be a burnt contact? Doesn't really look like it. I know the connectors at the alternator and the regulator don't look good. I could check the wires for a break I guess. I know it is boiling the battery if I leave the key on when it is running and lugs the engine horribly. So what would keep that from being energized?

"the connectors at the alternator and the regulator don't look good"
Had to replace my connectors, too.
Wish I had replaced them before they shorted and burned.

 

[EBGwd59]

the wires were broken at the connectors and this is the first I have noticed the problem with the lights and charging. I will give this a try tonight when I get home from work. Is there an easy way to get the female spade out of the plug? I had a hard time with this on the one I replaced.

Had to replace mine, too. 40+ years old.
Wish could have fixed before they shorted out and smoked.