New voltage regulator on 129 shorts wiring, what's up?

[nothercrash]

Hi. I recently installed a new voltage regulator on my 129. I had already replaced the generator and triple checked all the wiring, so a broken VR was causing my no charge condition. The tractor runs well otherwise, and mows every week.

I bought a new regulator over the winter (don't remember exactly where from), and was excited to put it in, and put away my battery charger. I connected the ground wire, then the field wire, but then I ran into a problem. The VR I had removed from the tractor had terminals for ground, field, batt, and gen. The new VR had terminals for ground, field, G, and L. I did some research, and found that L meant load, and G still meant gen, so I tried to hook the wire that had gone to batt on my old VR to L on the new one, and the terminal sparked, and the engine started turning over. I immediately pulled it away, rechecked the wiring and retested about 100 times, but I couldn't make any combination work. I finally opened up the two VR's to compare their circuitry, and the problem was obvious: the new VR (F, G, L) had the G and the L terminals connected internally, while the old VR (F, G, B) did not have its G and B terminals connected. The new VR completed a short circuit from battery to starter.

Do I just have the wrong style of voltage regulator? I'm sure I ordered one that was advertised as being for a 129. Is there any rewiring I can do to make this VR work?

Thanks for any help guys, Alex

[ol'George]

I'm going to guess wrong Regulator
F terminal goes to Field on Start/Gen.
G terminal goes to "G" or sometimes stamped A (Armature) on S/G
L terminal is usually used for lights or a load ( not usually needed)
Ground is usually through a braided wire near rubber mounting feet,
but not always.
A dedicated Batt terminal is needed.
post a pix of new reg. something don't sound right.

[R Bedell]

Did you buy the correct V/R as contained in this link...??. V/R

Is your tractor wired as per the OEM Wiring Diagram...??

[cubs-n-bxrs]

Don't some of those aftermarket V/R's have the terminal on the bottom that needs to be wired as well? Seems like I remember the V/R I acquired from NAPA many moons ago had a terminal on the bottom.

[ironman]

Originally Posted by nothercrash

The new VR had terminals for ground, field, G, and L

Ground, Field, G, and L. So are you saying there are two terminals for ground wires?? A picture of this might help.

[b.d.d.]

I have a similar issue and am heading out to the barn to work on it now. My OE Delco VR had 3 terminals and went bad (ground broke, corroded, etc)

My only available option was a 4 terminal VR, with the additional terminal showing up on the back side and not marked, but apparently this is supposed to be the G terminal that goes to A post on the S/G.

Additionally, like yours, the 3 remaining terminals on the new VR do not jive up with markings on the old VR.

So as previously mentioned, I belive all we should have to do is:

* Ground VR to where it mounts (ensure braided wire is grounded)
* G terminal on back to the A post of the S/G
* B or BATT terminal to 12V+ constant
* F terminal to the F post of the S/G
* L terminal to light switch if you have lights...if not, to nothing

Hope this helps. I’ll let you know what happened on my end this evening.