If the belt was routed correctly around the idler pulley and motor the belt switch should be closed so that it will run. The belt switch will have a pink and a brown wire attached and it should be close to idler spring mounted on the motor bracket or base. The idler pulley spring rod should not be striking the switch. When the belt is off or broke the idler pulley spring rod will strike and lay up against the belt switch and it opens the switch to keep it from staying running. According to the wiring diagram your dryer should still start and run if you push and hold the start button. The broken belt switch will keep the dryer from staying running, but it should start and run as long as you hold the start button in. Now if one of the door switch wires came loose or you did not get the wires back on the dryer is not going to start.