B21 (2007) PTO Turning engine off?

RobbieBones · Apr 15, 2015

I removed my backhoe for the first time and tested my PTO (not that I needed to) and when I engage the PTO lever downward I hear a click and the engine just turns off. Click sounds like it is coming from the engine compartment. Backhoe lever on right side of seat is in the PTO position. I see the switch that the pto lever operates on the left side of seat and cleaned it, same results. Could it be the seat safety switch on the right side of seat? Any other switches to look for? There is no attachment on the PTO. PTO shaft turns easily by hand with the tractor off. Any ideas?

kubmehc · Apr 15, 2015

The seat safety switch is the first place to start.

RobbieBones · Apr 15, 2015

After posting I found that the safety switch under the right hand side of the seat (when your sitting) had a jumper wire installed in it (What is this switch for?). This is not the seat switch (with the plastic lever) it is the one attached much lower. It maybe in connection with the forward and reverse/neutral position of the pedal. So I then used a piece of wire to jump the lead to the switch attached to the PTO lever under the left side of the seat and the PTO engaged and worked fine, engine did not turn off. Great now all my safety switches are bypassed!

That is not how I want to operate the machine. I bought this machine used with around 800hrs on it. In the past I used just the backhoe and front end loader but know that my sons are older and I plan on using some attachments, mainly a tiller, I would like to make sure that the safety switches are working correctly. I believe there are three safety switches, one for the actual seat, one for the pedal, one for the PTO, how are they suppose to work?

Also under the right side of the seat there are two plugs that had nothing attached to them, anyone know what they are for?

kubmehc · Apr 15, 2015

Most likely the seat switch failed and that's why they had the HST pedal switch jumped. May be the work light/backup alarm harness connectors

PILOON · Apr 16, 2015

Most of those safety switches a micro switches and very sensitive to corrosion due to their locations and exposure to damp conditions.
Rather than replacing a great many operators bypass them once they fail or start acting up.

While as a generic switch they can be found very inexpensively (like under $1.00) the typical dealer probably wants $10-20.

RobbieBones · Apr 16, 2015

I think I narrowed it down to the seat switch. First I reconnected the pedal switch and the PTO lever switch with no jumpers. Next I jumped the seat switch by jumping the two outside leads in the plug. Started the machine and everything operated including the PTO. I then pulled the jumper from the seat switch and the machine turned off. So I'll be buying a new seat switch.

I've had the machine for 7 years and never really realized how unsafe I was operating it.