Working on a Whirlpool Duet dryer, no heat, sometimes pops the breaker. Found an open around the heater, motor area. Checked motor switch, seemed ok.
Put it back together, still didn't work and customer couldn't afford a new motor which I suspected was bad.
Took apart the slim, black plastic centrifical switch, compared it to an old one. The factory left out the coil spring that puts pressure on the heater contacts. Apparently,
the leaf spring that keeps the contacts closed deteriorated after years of use. Added a spring, fixed problem. One more way to cheapen production costs, but cause problems later!