The machine won't start... it's been working fine

Rinse on most washers is cold water your wash cycles can be cold hot and even warm. Problem You may have is a bad water feed valve Or Timer and possible bad wire harness at motor to timer
check water valve Turn washer to regular wash cycle pull knob on will washer fill ?
if water starts to fill then change washer temp if washer has this.
if water comes out on all settings water valve is fine.
Check the water both hot and cold that it is turned on;at faucet.
Your Kenmore Most likely has a bad water valve check for hot water side clog or not working.

If this is a top load washer; then the "LID Switch" is broken. Go to www.sears.com/parts, enter your model number and you'll see the switch listed.

Sounds like this could be a blocked/air-locked filter.

easy fix if so.

First. switch off the Machine at the socket.
Check your washing machine user manual for the location of the pump filter access screw. (Normally situated behind a front bottom clip out panel) ensure you have a few towels and a couple of pans/dishes at the ready before releasing the access screw, expect two or three litres of water to drain... as well as whatever is blocking the filter. (could just be an air blockage or a small object) replace the filter screw and clip off panel, switch on at mains.

Hope this helps.

Good Afternoon Leszek - Thank you for your question. Based on the symptoms you are describing it sounds like the unit has a faulty timer or a potential wiring failure. Try reprogramming the unit by either unplugging it or flipping the household circuit breaker to the off position. It is important to wait approximately ten minutes and then turn on the unit. If issue persists, then at this point I strongly suggest reaching out to a professional that can accurately diagnose and repair the washer.

You have a timer problem, the contacts are welded in spin mode.
This is almost always caused by advancing the timer by hand when the dial is pulled out in the "ON" position, causing arcing of the contacts.

Push down on lid or lid switch.

There should be a spring clip that holds the timer knob on. It or the timer knob may need replaced. Here is a picture of the timer knob and the spring clip. Sure hope this helps and best wishes.

lid switch

on the inside of the timer switch hold the shaft that the Knob is on with a pair of needle nose pliers and pull the knob from the front. " Gently"