Belarus 925 starting - wiring

[xprdq]

I have a Belarus 925 and I think the prev owner left me with wiring problems, but I'm just guessing.
Right now I'm looking into the Starter Relay and the 'other' Starter Relay (the one that I think has something to do with locking out the starter if the tractor is in gear) Is there anyone out there that can tell me what each of the wires on those two relays are for, where they each go (or at least where they're supposed to go) On the larger Starter Relay I have already figured out that the orange wire is 'power in' (but I'm not exactly sure where it comes from) and that the purple wire is 'power out' and goes to/powers the solenoid when the key is turned. I think that I also have the rest of that relay's wires figured out, but I'm just guessing so I'd rather have someone tell me that isn't guessing.
I have no guesses yet about the other relay's wires -so help there would be really great. I have a strong feeling that one or more wires may be hooked up incorrectly at the moment and causing my starting problems.

 

[Bison]

What exactly is your starting problem?

 

[xprdq]

Only 12v is being sent to the starter. Voltage tests on the regular starter relay (the relay marked with a picture of a starter) suggest that it is getting what it needs and is working properly but nothing seems to happen with the other relay (the relay marked with a picture of a starter and a lock) when the key is turned on. So I'm guessing that something is supposed to be sending power to that relay at start time but isn't. If I knew what is supposed to be sending power to that relay I could go and check that item(s) directly.

As a side note: I have seen changes related to when the tractor is in gear vs neutral, so it seems that the neutral safety switch is working properly, but I can't find the switch to inspect it directly. Other sites have said that it is under the cab to the right of the driver's seat but all I found down there was a switch/button that controls the back-up lights. There were no other apparent wires or switches in the area. Do you know where that switch might actually be?

 

[Bison]

Is your belarus the old style(sheet metal dash) or new style(plastic dash)??

Do you have a 12/24v series paralel switch on it (located between batts on new style dash models)?

 

[xprdq]

I have the cheap-o plastic dash and the 12/24v switch between the batteries.

 

[Bison]

I have the cheap-o plastic dash and the 12/24v switch between the batteries.

I suspect the PO has bypassed the series paralel switch if it starts on 12 volt

 

[xprdq]

Actually it fails to start (or turn over at all) at 12v. I replaced the starter & solenoid because I had assumed that was the problem before I started checking voltages. (It had the original 24v starter and I replaced it with a new one, a gear reduction model.)

 

[Bison]

Is the paralel switch working?

Its a heavy relay solenoid that sends 24 v (batts in series)to the starter once you turn the key but allows the alt to charge 12 v to the individual batts once the engine runs.

A 24 v starter wont hardly turn over on 12 volt

 

[xprdq]

The parallel switch isn't sending 24v to the starter, but I'm not sure if it isn't working or if the signal/juice isn't being sent to activate it.

I'm assuming that one of the poles on one of the relays is supposed to send juice to activate the parallel switch, but I don't know which one so I haven't been able to test and see if it is happening.

 

[Bison]

If you don't have already,i advice you to get a operators/service manual for that tractor.
The wiring schematics are in there so you can do some testing.
Its a kind of complicated procedure to walk you trough over the internet.