Maytag model # MVWC300VW1 timer not advancing past rinse cycle.Most times I have found when a timer simply stops at the rinse cycle it generally has nothing to do with the timer. Almost all rinse cycles are cold only, do you see the issue. When most people find there washer working normally until it gets to the rinse cycle they assume there is a issue with the timer. Most of the time the cold water valve is defective or the cold water has been shut off. If you have the washer set to warm water it will fill like normal in the wash cycle and then stop in the rinse, cold water only rinse cycles remember.
The number one way to check to see if the timer is the issue is to try different cycles, you may only have used the normal wash cycle. Check to see if the washer works good in any other cycles. Chances are if the timer is freezing up in just one of your wash cycle and not the others it time to replace the timer. For this model the part number is W10175557 Timer.
The very first thing to do is to check the incoming water lines, screens and water valves.