My neighbour gave me his T1400H. By design you can't get off seat with blades PTO engaged (lever). You can get off if pto is off. Maybe it is because of older safety features or because the hydro drive by pedal should seek neutral if no operator. I want it so you can only leave seat if pto is off and brake is on. It's being a bit of a challenge. The safety switches all pass 12v to a relay pack (relays not accessible) rather than grounding the kill circuit directly. The seat switch is single pole and no easy way to replace with double pole or add additional switch. Brake was single pole but I was able to add a second switch. The part that's complicating it is that the PTO switch circuit enters the relay pack to control 2 relays. However it exits the pack to feed the carb solenoid on the same connector that's inputting to the pack and feeding carb from the seat switch. There's an internal diode to prevent seat input affecting crank circuit. The effect is that if I try to use the seat +ve feed it's in parallel with PTO. So if PTO is off it's also like saying your are on the seat. Despite the schematic showing this I still tried first 1 relay , then 2 in the feed to the carb solenoid . I'm thinking now that if I put a diode in the right place in the feed from seat to relay pack then I can isolate the feed to my new relay from the seat and have no signal to it from the PTO, while still having the seat feed the relay pact and the carb solenoid.
I'm assuming that a diode from a briggs dual charging setup should handle this. I notice that the relay pack schematic shows diodes across the relay coil connections. How important is that to have on the relays I'm adding?