A Kenmore dryer may refuse to heat up for reasons including a blown fuse or a tripped gas valve. A dryer's refusal to head may also be caused by overloading or a clogged vent.
The first thing to do if a dryer refuses to heat is to check the gas valve by looking to make sure the valve is on, then checking that the gas is flowing. If that doesn't work, a blown fuse may be the issue. The owner can check fuses by opening the front panel. The dryer also may be overloaded, so removing some clothing may help.