Should I repair or replace this Dishwasher Timer?

Suspected bad part: Frigidaire Kenmore Dishwasher Timer

Unit does not advance to the dry cycle. The included manual says a thermostat could also be bad. The timer is about $130 to buy online.

Should I first simulate the thermostat signal going to the box and see if it works then? Do the Frigidaire Kenmore Dishwasher Timers sometimes fail? More often then the thermostat?

My dishwasher is about 9 years old.

Thanks for any help!