I have a Turf Tiger SST/61A serial # 545xxxx with 25 HP Kohler. Replaced the PTO clutch less than a year ago (it was completely worn out), PTO switch, and recently the ECM. I was having a previous issue with the PTO switch not engaging. I have checked all safety interlocks and they are fine. With the engine running I can engage the PTO and the voltage on the light blue wire from the ECM goes from 12+ to 0. I assume the light blue wire is what actually energizes the PTO clutch. I can bypass the PTO switch with a toggle switch and the clutch engages immediately so I am confident it is not the clutch or wiring to it. Is this likely a poor ground? Any ideas?