I have a gas dryer, Kenmore model 110.73952101 . It lights up and heats but the motor does not run. I have replaced the motor and the timer, and eliminated the relays and door switch. The motor was an exact replacement so I am sure the wiring is correct, same with the timer. When I push start, it clicks, low hum from the control board, ignitor warms up and gas lights, but motor does not run. Any ideas? I'm not so sure the old motor was bad, it does turn... but the new one turns much easier, so I am leaving it in.

Did you ohm out the safeties? Trace the power wires until you find the open safety. They are all wired in series, and a gas dryer has a few more than an electric dryer. You have had it long enough that it surely needs to be cleaned, too. I doubt very much you ever even needed a motor. Make sure power leaves the timer and goes to the motor. You can put one ohm meter lead (with unit unplugged) and put it on the terminal where the power cord attaches and move through the drier until you find the fault. It's very easy to do. Look at these manuals until you find the one that matches yours: https://dl.dropbox.com/u/8010163/Whirlpool%20Dryers.zip
https://dl.dropbox.com/u/8010163/How%20to%20use%20Test%20Equipment%20Service%20Manu al.pdf

I don't know how to do this... I didn't see any manuals that looked like mine. I'm down to thinking it's the dryness control board because I've tried everything else. We don't even use this so I'd like to just bypass it but don't know how. Thanks for your advice though!

Have you checked your sensors? You will have to check them and clean them. The circuit boards are controlled by the sensors, and if they are dirty you can spend a lot of money for nothing and still not fix it. Get a meter and learn how to use it, or just replace every part in the dryer until you guess right.