Dryer won't start, is it the start relay switch or

First verify 220 volts of power to the terminal where the cord attaches. If voltage is OK,remove the rear panel and locate the thermal fuse on the left of the exhaust vent. It is 1 and 1/2 inches long by 1/2 inch wide and white in color. Turn off the power to the dryer. Remove the wires from the fuse. Check the fuse with a volt/ohm meter set for ohms. No reading is a bad fuse. If you get a reading,check the door switch for continuity.