Engine PTO Clutch Not Engaing

Thanks Joe. I got the service manual online with all the wiring schematics. I'm starting with the PTO switch making sure that the proper colors are attached to the proper parts of the switch. I'm not good at reading wiring diagrams but will take my time...

So far I have tested the new PTO clutch with a 12V source and it does the click&clack. I went to John Deere and picked up a new PTO switch and installed it. When I start up the LX172 and pull up on the PTO switch the engine quickly slows for a split second and continues running. So now I'm thinking that this has to be something to do with the parking brake? I know that the seat cutoff switch works because when I get off of the mower it shuts off. So that's why I'm thinking the parking brake is not working or maybe the foot brake pedal is interfering with the circuit. I'm not good at reading schematics but here it is..... Thanks for your help!

Well its been a while and I thought I would uncover my old lx172 to see if I can finally get the PTO clutch engaged.
Its nice weather here in Franklin Tennessee today. This is what Id did.....

- I took off the PTO clutch which is brand new from JD and did a OHM check with my multimeter and that read 2.8. So I think I'm good there.
- I have a brand new battery that reads 12.5 V on my multimeter. I also checked the charging of the battery with the engine running and that read 14v. So its charging.
- I checked to make sure that the electrical connector from the pto switch to the clutch was getting power when the PTO switch was pulled up. It did get the 12volts - so I know the clutch is getting juice.
- I checked to make sure the seat switch off was working- the engine shut off when I got off the seat with the PTO switch in the ON position.
- So I sat down on the Deere and started up the engine (which runs great!) and pulled up on the PTO clutch and it just sort of clicks but when I turn off the PTO switch it does a whoosh almost like a release of air.

So that's where I'm at now. Engine runs great but cant get the PTO engaged. What else should I do? Do I need to check the clutch gap with a feeler gauge? The clutch is brand new though.


Update: Well I'm the idiot today. I put my iPhone under the mower to see what was happening to the clutch when I pulled up on the pto switch. Wouldn't you know that the clutch engaged! -started spinning. I was thinking that I would hear the roar of the blades turning but I had no deck installed duh. So I'm assuming when I get the deck on all will be ok.