The dryer will not start. There is power to the unit, I have replaced the door switch and the thermostat control but still will not run. When unit is plugged into power there is a "clicking" noise from the timer unit that doesn't stop regardless of the postion. Suggestions? Thank you.

Here is your parts breakdown a wiring diagram is included
Model CDE22B6V

The ticking is probably the timer.

Use timed dry to troubleshoot, it is the easiest.

Circuit path is NEUTRAL / THERMAL FUSE NON RESETTABLE / DOOR SWITCH C to NO contacts / MOTOR / START SWITCH / TIMER contacts L to M / L1

Once the motor starts the MOTOR CENTrifugal SWITCHes trip, this removes the AUX (start) winding from the circuit and the RUN winding now gets power through the TIMER contacts L to M. Also the other MOTOR CENT SWITCH switches in the heater circuit.

Timer contacts L to M should be closed except when timer is at OFF
Timer contacts L to TM should be closed for the entire timed dry cycle, they are not closed for most of the AUTO cycles as the timer gets it's power from a different circuit path.

If your THERMAL FUSE NOT RESETTABLE is blown, be sure to give the interior a good cleaning including the blower wheel. Also clean and check your vent system.

The best/safest way to check the fuse is with a meter.
If you do not have a meter you can
Unplug the unit
Short the two wires to the fuse together
Tape them together so they cannot short to anything
Plug it in and give it a try.

If shot replace both the Safety Thermostat (High Limit) and the thermal fuse as shown in Gene's post, they come both are in the kit.

That is the wrong item, it is the cycling thermostat.

The ones you want are on the heater case.
Model CDE22B6V

Heater section Item 5. High limit and thermal fuse.