Whirlpool gas dryer, no heat, timer doesn't advance

Dryer runs, but has no heat. Timer will not advance using “Automatic”. However, it will advance under “Timed”. Neither cycle has heat.

Based on some other posts, I suspect the solenoid coils. Is this correct, or should I do something else first.

Purchased the solenoid coil kit. Installed them in 10 minutes. Problem resolved.