The auto mode is controlled by two t-stats. One where air exits for reheating and the other where it enters drier drum. I would suspect they are out of calibration and need replacing. They have numbers stamped on them for different temps and are oval with a screw on each end and two wires. More than likely your drier is dirty which can also cause the problem. Dirt and lint residue build up on the inside of the air passages and block the sensors. You have to disassemble the drier and scrape and wash out the parts, except the motor-vacuum it out and then clean out blower fan, too. Don't be shy about taking it apart-the dirt builds up everywhere and will cause a fire. Then clean out exhaust vent pipe. This will probably cure your problem. DrTom4444

What "plate" are you talking about? DrTom444

There are two t-stats that regulate the auto dry cycle one where air leaves drum and another where air enters drum. One or both are bad or there is dirt and lint buildup on the ducts. Clean it and it will probably fix it. DrTom4444

I had the same problem and the repair man told me the fabric softener sheets coat the moisture sensor which should be cleaned from time to time or better yet don't use them.