Warm wash is almost cold (no different from cool wash). hot water works fine.

Wrong water line. Go a head swap the water line. You should be good to go.

Good luck

Mai

change water valve

What is the model number?

How hot is the water temp in the house that you are in? If the inlet hose to the washer is not hot, then it is not the washing machine.

my last two washing machines, totally different brands and types, did the exact same thing. It must be a new way of setting them up, I don't understand either. I can't get straight hot water. My new one does seem hotter than the old one I had which was very distinctly hot then cold then hot then cold even on hot hot water.

check wire on water temperature switch 1 wire loose or defective or switch defective

If the cold works on cold wash but the hot don't work on hot wash . Then yes the switch is bad.give What model is it?

Most washing machines do not heat water, they merely let the hot water into the wash tub that comes from your house hot water heater.... when selecting warm, hot and cold water will be mixed together to get warm or when selecting cold.. only the cold water is allowed into the wash tub.. Please provide brand and model number of machine so I can tailor a reply toward your specific washer...

The temp is controlled by a thermistor to make sure the warm water is warm. If the incoming cold is too cold, or the incoming hot is not hot enough, it will compensate by turning off the cold until the temp comes up, then it should turn the cold back on. Make sure the hot supply is to the hot water valve. If the hoses are backwards it won't work right either. Or you may have a bad solenoid in the water valve. It's possible for a water valve to work when it's cold, but as electricity runs through it, the solenoid heats up and causes it to open electrically which will close it mechanically and turn the water off. Usually if this is the case it won't open again for at least 10 minutes until the solenoid cools down enough.