My Kenmore HE3 will start and run, flame wiill ignite and run for several minutes but will not relight when dryers calls for heat. Glow plug turns on but gas valve will not open. I have continuity through gas valve coils, thermistor,Thermal fuse, highlimit thermostat and flame sensor

It sounds like the safety is turning it off due to a build-up of dirt lining the air ducts and blower. You will need to totally tear it down and clean it out well before going any further. Then look at these and use a meter: https://dl.dropboxusercontent.com/u/...%20Manuals.zip
You will need a good volt/ohm meter to test it.