[971821]

Putting my 318 back together after bunch of work.
On good side the linkage slop and surge is fixed.
Started up good but when going to mow the PTO was inop-ran fine prior.
Wondering what I did to make it not work. Retraced what had changed. Had pan off. Did not mess with any wiring other than disconnecting seat, pulling battery and taking 25A CB off for painting.
Not great with reading electrical schematics, but did some trial and error troubleshooting and eventually got PTO running normally, just do not think I solved the problem the right way.
First verified seat switch works as designed.
With ignition switch on, cycling PTO switch did nothing. No engagement clunk.
Cleaned the ground wire at bottom of PTO. Still did not work.
Found a loose black bladed wire between the dash and battery, wondering what it was and if this had been disconnected.
Gator clipped it to ground and PTO engaged when cycling switch.
Started up and PTO worked normally.
Is this loose black wire for the uninstalled rear PTO or does it attach somewhere that I cannot find?
I permanently attached it and mowed this afternoon- no issues.
If I did not fix it right, maybe someone can help.

Thanks in advance.

 

[bloodrunsgreen]

There is one black wire that is for the second PTO (rear) that is for the lamp on the dash.

 

[971821]

I guess my question should be modified to ask if there are other safety switches other than the seat and maybe the speed control (which the PO bypassed) that might shut down the PTO with interrupted or severed connection. Guessing that is the problem.
With original problem when I engaged the PTO switch it would kill the running engine, I guess because the seat switch was not connected. When I connected the seat switch the engine would continue to run when engaging the PTO switch but the PTO would not engage.
Still curious why grounding the unused loose rear PTO black blade wire made it work.

 

[Rhoderman]

My GT225 has a switch that kills the PTO when the reverse pedal is used. Does yours have that?

The safety circuit is a series loop of switches that need to be closed to allow it to turn on (or kill) the PTO. You have bypassed these with your jumper wire, so you know one of those switches is open. Congrats, you're well into learning "Electrical Troubleshooting 101"! Follow your diagram, and short across each switch that could be inhibiting operation, one at a time. I think it will be an easy fix for you.

 

[bloodrunsgreen]

My guess is that there are more hacks in the harness. Do you have the TM1590 manual which would help you check the wiring out? It would be a slow process but would help you learn everything about the 318. One thing is that the PTO switches have two sides in use, one to operate the PTO, the other side (second pole of the switch) is used in the safety circuit. With the machine being well into it's 30 years a switch can fail (either side independently or both sides). So check that switch operation. It is a DPST switch.

Also depending on your serial number after 1990, there is a brake switch that is used in order to start the tractor.

 

[971821]

I

My guess is that there are more hacks in the harness. Do you have the TM1590 manual which would help you check the wiring out? It would be a slow process but would help you learn everything about the 318. One thing is that the PTO switches have two sides in use, one to operate the PTO, the other side (second pole of the switch) is used in the safety circuit. With the machine being well into it's 30 years a switch can fail (either side independently or both sides). So check that switch operation. It is a DPST switch.

Also depending on your serial number after 1990, there is a brake switch that is used in order to start the tractor.

Thanks.
Have the manual and a spare parts tractor. Will start with a PTO switch change then proceed through others.. Tractor is a 87, no brake switch.