Volfandt
Veteran Member
I'm linking to an old thread where we stepped through a similar problem on a BX23. The BX25 "may" still retain the same method of operation.
Good luck
http://www.tractorbynet.com/forums/...x23-solenoid-location.html?highlight=volfandt
From post #7:
All-righty then, armed with my trusty multimeter and a hard copy of the WSM schematic, I've got some readings and I believe an idea (dangerous, I know ) on how the D905 stop solenoid and assoiciated safety switch operations work on my BX23.
The solenoid itself is normally in the "run" position and is temporarily electrically energized to "off" (to cut off fuel flow in the injector pump).
You can physically disconnect the solenoid and the engine will start & run but of course you'll have to manually use the shutdown lever to shut it off. And you'll also not have any safety shutdown features either. It does not use a "holding" voltage or coil for it's run operation. It must rely on spring tension alone to return the solenoid's plunger to the normal (run) position.
There are two wires feeding to the stop solenoid, a white and a black. The black is tied to permanent ground and the white is connected to the Timer Relay which is located under the dash.
The timer relay controls the voltage to the stop solenoid. The timer relay has two different input voltage circuits that control it. One input circuit has a 15amp fuse and is always hot.
The other input circuit has the 20amp fuse and feeds through both seat switches and the pto switch, the HST pedal switch and is turned on/off via the key switch.
The reason for two inputs to the timer relay is two fold. The always hot input is the actual working voltage that is passed on to the stop solenoid.
The other input that goes through all the safety switches is used to actuate the timer relay and also to power the delay timer circuitry. This is the "control" circuit.
When all the safety switches are in the correct positions (made or shorted contacts) and the key turned on, power is applied to the timer relay though the control circuit. There is NO 12v applied to the stop solenoid. The engine is started and the stop solenoid stays in its unpowered unenergized state.
If one raises up from the seat and with the pto engaged (except in the rear only position) and/or depresses the HST pedal voltage is removed from the timer relay "control circuit" which inturn causes it to immediately apply 12v to the stop solenoid for approx 10 sec's, then the timer relay clicks off and voltage is once again removed from the stop solenoid. 10 seconds is plenty enough time to shut down the D905.
When the key is turned Off it basically removes 12v from the timer relay in the same manner as a safety switch "tripping" which causes the timer relay to apply approx 10 sec's of 12v to the stop solenoid.
Well thats my theory of operation so lets get to some troubleshooting tips.
1) unplug the stop solenoid and using a multimeter or even a 12v lamp, plug one lead into the black recepticle and the other lead to the white recepticle.
Turn the key switch on, you should NOT read any voltage. If you do the timer relay is bad. (note, I've not read of one of these ever going bad yet but anything can fail).
2) Now turn the key switch off. You SHOULD read 12v for approx 10 sec's then it should go away. You will also hear the timer relay click under the dash. (it is not as loud as the stop solenoid click but you can hear it click).
If you do get this reading then your stop solenoid is bad.
3)If you do not get 10 sec's of 12v then the timer relay is bad OR one of the safety switches are not "making" OR(and more likely) the 20amp fuse is blown. The 15amp fuse could also be blown but the 20amp fuse is the main culprit as it also feeds the aux "hot" connector located under the seat that alot of folks like to use to power ROPS lights etc.
Good luck and let us know what you find.
Good luck
http://www.tractorbynet.com/forums/...x23-solenoid-location.html?highlight=volfandt
From post #7:
All-righty then, armed with my trusty multimeter and a hard copy of the WSM schematic, I've got some readings and I believe an idea (dangerous, I know ) on how the D905 stop solenoid and assoiciated safety switch operations work on my BX23.
The solenoid itself is normally in the "run" position and is temporarily electrically energized to "off" (to cut off fuel flow in the injector pump).
You can physically disconnect the solenoid and the engine will start & run but of course you'll have to manually use the shutdown lever to shut it off. And you'll also not have any safety shutdown features either. It does not use a "holding" voltage or coil for it's run operation. It must rely on spring tension alone to return the solenoid's plunger to the normal (run) position.
There are two wires feeding to the stop solenoid, a white and a black. The black is tied to permanent ground and the white is connected to the Timer Relay which is located under the dash.
The timer relay controls the voltage to the stop solenoid. The timer relay has two different input voltage circuits that control it. One input circuit has a 15amp fuse and is always hot.
The other input circuit has the 20amp fuse and feeds through both seat switches and the pto switch, the HST pedal switch and is turned on/off via the key switch.
The reason for two inputs to the timer relay is two fold. The always hot input is the actual working voltage that is passed on to the stop solenoid.
The other input that goes through all the safety switches is used to actuate the timer relay and also to power the delay timer circuitry. This is the "control" circuit.
When all the safety switches are in the correct positions (made or shorted contacts) and the key turned on, power is applied to the timer relay though the control circuit. There is NO 12v applied to the stop solenoid. The engine is started and the stop solenoid stays in its unpowered unenergized state.
If one raises up from the seat and with the pto engaged (except in the rear only position) and/or depresses the HST pedal voltage is removed from the timer relay "control circuit" which inturn causes it to immediately apply 12v to the stop solenoid for approx 10 sec's, then the timer relay clicks off and voltage is once again removed from the stop solenoid. 10 seconds is plenty enough time to shut down the D905.
When the key is turned Off it basically removes 12v from the timer relay in the same manner as a safety switch "tripping" which causes the timer relay to apply approx 10 sec's of 12v to the stop solenoid.
Well thats my theory of operation so lets get to some troubleshooting tips.
1) unplug the stop solenoid and using a multimeter or even a 12v lamp, plug one lead into the black recepticle and the other lead to the white recepticle.
Turn the key switch on, you should NOT read any voltage. If you do the timer relay is bad. (note, I've not read of one of these ever going bad yet but anything can fail).
2) Now turn the key switch off. You SHOULD read 12v for approx 10 sec's then it should go away. You will also hear the timer relay click under the dash. (it is not as loud as the stop solenoid click but you can hear it click).
If you do get this reading then your stop solenoid is bad.
3)If you do not get 10 sec's of 12v then the timer relay is bad OR one of the safety switches are not "making" OR(and more likely) the 20amp fuse is blown. The 15amp fuse could also be blown but the 20amp fuse is the main culprit as it also feeds the aux "hot" connector located under the seat that alot of folks like to use to power ROPS lights etc.
Good luck and let us know what you find.
