Craftsman Garden Tractor with snowthrower attachment questions

I have a Craftsman 26 HP Garden Tractor (model # 917.28947)with 54" mower. I have the 42 " snow thrower attachment model number 486.24837 which i am happy with and have used for three storms this winter and half of a fourth storm before my problem. I shut off the tractor to do something and it wouldn't start a few minutes afterward.(its possible I tried to start it with the PTO on but after I shut off the PTO it still wouldn't start). Dead silence.I jumped the battery to solenoid and it started and ran ok but would not start with key. Also the snow thrower would not engage. I pushed it into garage and later fiddled with it and tapped the seat switch and it started normally with a key but the snow thrower still doesn't engage. It is not jammed or anything. I raised the rear wheels on some ramps and looked underneath. It appears the drive motion belt is flopping around loose but the tractor drives fine?? I think this also drives the electric clutch? Maybe not. I have two questions. When the tractor is not driving does the drive belt sit loose on pulleys without any tension on it? How on earth can the tractor drive like that without any squealing or anything? Does the belt tighten up when the accelerator is pressed? I need to know because i am trying to determine if this is what drives the snow blower attachment or does the electric clutch turn independent of the drive motion belt? My problem is the snow blower doesn't engage and the drive motion belt looks suspiciously loose. This tractor is under warranty for more than another year but it will take three weeks for someone to come out. I need to get this snowthrower working or have to buy a back up snowblower because we are getting slammed with snow this winter.

 

I found the problem. It was a loose belt on the snow thrower mechanism (which has two belts.)I tightened up the tensioner a couple links and that did it.I put the tractor on jack stands and bypassed the seat safety switch so i could watch the undersides while I switch the PTO on and off. The electric clutch was kicking in but the mechanism wasn't turning.

I also learned something about the main drive belt of the tractor. When the park brake is on, that totally loosens the drive belt, so that is why I saw it loosely flopping.The park brake tightens the tensioner when you release the brake.