I have a GF 1800 mower (diesel, hydrostatic) that the motor shuts off instantly when you engage the pto for the mower blades to run. I installed a new safety switch for the pto lever thinking that was the culprit. I removed the seat and jumped the seat safety switch and same thing still happened. I then jumped the pto kill switch on the other side of the mower and still no luck. The mower runs fine and the blades turn freely. I had a pack rat visit recently but I can't see any damage to the wires, in fact I can't tell where the wires start and finish as they are in conduit. What to do?