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Here is a wiring diagram
https://www.servicematters.com/d...0Sheet%20-%208528190.pdf

while pushing the start button the dryer will only turn on in the air dry mode and not on any other setting on the timer
I assume that you mean that the motor will not start and in Air Dry it not only starts but the cycle runs correctly. Also the unit seems totally dead in any mode with a temp setting other than Air Dry.
Very, very strange as temp setting should have no effect on the starting of the motor. As you can see from the timing chart Air uses the same contacts, circuit path as the other modes except that BK/R (heater) timer contacts are not closed.
I assume you have tried both Timed and Auto cycles.

is this my timer?
Could be the timer cannot say for sure.

you can hear it clicking while running it thru the cycles manually.
The question is does the timer advance?
Note: it is hooked directly across the 240 volts in timed dry mode.

You motor runs on half the line 120 volts (L1 to Neutral).
The heater and timer run on the full line 240 volts (L1 to L2).