Dlt 25 hp with 48" deck-blades will not engage

Welcome Road69runners. :howdy:

Could be either the clutch is not getting power to it or has failed. First I would check the wires to the clutch and try to follow them back up to the switch or relay someplace and make sure no wires look broken or have loose connectors. Also if you have a voltmeter try to determine if 12Vdc is making down to the clutch.

(Might want to pull the deck drive belt back off in case the clutch surprisingly activates while your are troubleshooting it.)

My first thought was that some corrosion from the winter exposure may have crept into one of the connections somewhere. Testing, as Mark suggested might just show you where the problem is.

I already physically checked the connections. I will check the voltage. Thx

If your voltage is on the low side that is probably the problem.

Do you hear any sound when you pull the PTO switch like a click or something? If you have plenty power in the battery it's basically narrowed down to an electrical issue.