Deck will not lower when fully powered on

Hi! My husband and I recently got a craftsman zts7500, when the mower is on the deck will not raise or lower and shuts off. But if it is on aux power the deck will raise and lower. We have adjusted the clutch after installing a new one, we have made sure the belt it routed correctly, and battery is fully charged. Also we did a continuity test on the PTO switch and that was fine. And we replaced the filter, cleaned carb and the filter new. And did tested for spark on the spark plug and it was fine. But still can’t figure out why the deck will not raise or lower when the mower is on and it shuts off as soon as we try to.