MalMac 1,332 #1 Posted January 13, 2015 Can anyone tell me if the Seat Safety Switch on a 1990 520H is normally open or closed. Was looking at it and don't see NC or NO on it anywhere. Share this post Link to post Share on other sites
rmaynard 16,211 #2 Posted January 13, 2015 Here is the spark circuit for your 1990 520-H. Looks like you have to be in the seat to complete the circuit. That means that the switch is normally open. When your butt is in the seat, it closes. 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #3 Posted January 13, 2015 I got this one backwards so corrected further down. Garry Share this post Link to post Share on other sites
buckrancher 2,694 #4 Posted January 13, 2015 Should be closed in both positions according to the wiring diagrams because there are 3 wires to 3 terminals - yellow, brown and orange. Yellow from the ignition switch Orange feeds the ignition circuit with the pto OFF Brown to the pto switch. With pto ON the orange feeds the ignition. Garry If it was closed in both positions the switch would be useless Brian Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,393 #5 Posted January 13, 2015 I got it backwards. Seat switch should be closed in both positions according to the wiring diagrams because there are 3 wires to 3 terminals - brown, red and orange The yellow from the ignition switch feeds the pto switch Pto OFF the orange feeds the ignition. Pto ON the brown feeds the seat switch The orange wire at the seat switch powers the ignition with operator in the seat The red wire at the seat switch should trigger the seat switch idiot light when the orange wire is not fed. Garry Share this post Link to post Share on other sites
MalMac 1,332 #6 Posted January 14, 2015 Ok thanks guys, I believe I have a seat switch failing. When PTO is engaged tractor will just die as if you got off the seat. Share this post Link to post Share on other sites
rick 252 #7 Posted January 19, 2015 I am having the same problem sometimes with my 416H. I have traced it to the worn out PTO microswitches on the right side of the tower. If I shake the wires, it will do okay for a while. The same problem will keep it from starting. Share this post Link to post Share on other sites
