Kitchen Gas Appliances - no heat for whilpool gas dryer

hi there, i have a whirlpool heavy duty dryer that is probably 6 or 7 yrs old. put a load in this am and went down to get the laundry and it was as wet as when i put it in. it worked ok the night before. i checked the vent for clogging and that was fine. i checked the gas line valve and that was still in the on position. i also checked the lint but knew that wasn't the problem since we clean that after every load, most times. i'm handy enough to change a part, not sure which one. would sure appreciate any suggestions. thanks in advance.

Do you have a flame observation panel you can remove to report back as to all that you see when you run it? I'd like to know if you ever see some ignitor trying to glow, down there, when you turn it on in a heat cycle.

Model #?