I have a Maytag dryer MDE8400AYW. The dryer worked fine, but then would not start (when I would pull the starter knob out) due to a bad timer. So, I went to a local appliance parts store and bought a new timer apparently that would work with this model. After inserting the new timer, the dryer started just fine again, but now the dryer does not stop...i.e., the timer does not advance at all, the unit just runs and runs and runs. This happens no matter if the unit is sensing the wetness of the clothes (the IntelliDry sensor does not advance from wet to damp to dry) or when I just use a timed drying cycle (e.g., set it for 10 minutes...it never advances at all). Thus, we must manually check when our clothes are dry or they will be toast. When I bought the new timer locally, the store's computer told them that I apparently also needed a whole new wiring harness for the new timer to work. I can't rewire the entire dryer! The original timer that we replaced did not have this problem, i.e., the timer advanced fine to stop the machine automatically when the clothes were dry.

I'm wondering if the letter coding on the top of the timers matter. Our old timer has 2 rows of letters:
H H H H D
H H H H

However, our new timer has these numbers:
M M H H D
M M H

Could this mean that one or more of the metal leads (prongs) is not active to make the timer advance?

The UGC label on the old timer is:
3087A MAYTAG 6 3720670 M285
KINGSTON 70959 - A00728

I noticed on the AppliancePartsPros website 3 replacement timers for my unit: AP4042962, AP4042973, AP4042974. Not sure the difference in the 3...their pictures all look the same on the website, but do show the same H H H H D, H H H H lettering as my old timer.

Do you know what the problem might be, and whether any of the timers on this website will make my dryer work fully?

Thanks so much!

Looks like there are archive data problems with this dryer. I would return the timer and call this parts site. They can reference microfish data on this and call the manufacturer for info. I personally never saw such a parts screwup, I accessed another parts site and they have even more timers to pick from. Have your serial # handy and production # if available.

Your original problem with failure to advance can perhaps be fixed by using non-residue contact cleaner available at Radio Shack, just advance the timer while spraying in any crease in the timer housing. Helps to loosten the screws a little.
I would get a "good" tech in there who loves a challenge like this and one not affiliated with Maytag. He/she can determine the problem.

Just for giggles I compared the part # for the wiring harness in my unit and it turns out I have a series 16 rather than the series 24 decoded by the serial # of the unit. You would think that someone at Maytag would have known to look for that after I called the second time. Such a simple solution. Guess Maytag changed the serial numbers but decided to use up the old wiring harnesses before opening a new container. Can't say as I blame them. Just wish they had let everyone else know about it. Thanks again for your help.