BX23S Low voltage on wire to starter solenoid

Micawber

New member

Equipment
BX23S, Z411
Nov 24, 2025
1
0
1
Louisville, KY
Hello — I’ve been troubleshooting an issue with my BX23S and could use some guidance. The tractor was running normally, then suddenly stalled as if a safety switch opened. When I attempted to restart it, the starter would not engage at all.

I went through all of the safety switches, and they appear to be functioning properly. I checked voltage at both seat switches and confirmed continuity on the PTO switch. Earlier this year I had a similar issue, and I added a starter-assist relay. I tied the Black/White starter-solenoid wire into the relay coil and fed battery voltage through the relay contacts. This seemed to be a common workaround and it had been working well.

Here’s what I’m seeing now:
  • If I disconnect the Black/White wire from my added relay, it reads 12V when I turn the key to “start.”
  • As soon as I connect it to the relay, the voltage drops to about 4V.
  • I replaced the relay, but the readings are the same.
I’m not completely certain where the Black/White wire originates inside the tractor. From the schematics, it appears there is an OEM start relay in the circuit. Under the fuse box I see two relays mounted together — one of them enclosed in a rubber boot.

Given all of this, what do you think the most likely issue is?