Grumpa,

I presume, you have a multi meter and aren't shy around 120 VAC .

At the gas valve coils, disconnect the harnesses,

Start the dryer on a heat setting , in the harness check across the Black and Red wires, you should have 120 VAC, if you do, you need to check the igniter/glow bar and radiant sensor(black box on side of burner flue) for closed circuits.

If No 120 VAC you'll need to check all the thermostats, on the blower housing and burner flue, they should all be closed circuits at room temperature.

From there you would need to access the control board, and check the gas valve relay for 120 VAC out to the thermostats and gas valve.

If everything checks proper, you'd have to have a bad set of gas valve coils,

Part number: AP3094251