Diagnose mower deck problems

[southmow]

Can anyone walk me through possible steps to diagnosing why my mower deck won't work? 

I think all the basic steps have been covered: the generator is off, it's in low gear, changed air filter, etc. 

I have looked at the 100 amp fuses. I think fuse A is for the Raven drive, not sure what B or the 75 amp is for. 

How can I find out if it is the deck itself, fuses, switches? 

Thanks for the help. 

[denny]

Unplug the deck, have someone sit in the seat and have unit running.. Pull up the PTO button and you should see a 12 volt signal on the two center (stacked) contacts coming from the unit. If not, there is a small switch somewhere up under there also hooked to the seat switch. Mine failed and was replaced.