Check the Water Faucets
You need to make sure the hot and cold water faucets are working properly, as this will help troubleshoot and isolate the problem with your Whirlpool washer. Make sure hot and cold water is coming out of the faucets.
To do this, you can disconnect the fill hoses from behind the washer after you turn the faucets off. Then place the hoses inside the washer basin and open them.
If you're getting good flow on both of the hoses, then there is something wrong with the washer.
Water Valve Filters
While the water valve hoses are off the machine, take this opportunity to check the water valve screen filters inside the water mixing valve where the hoses attach to the washing machine. These filters can become clogged with sediment or rust from the water that has flowed into them in the past.
It's not really worth the time or effort to try and clean them, so buy new ones at a washing machine repair store or hardware store, or order them direct from Whirlpool.
Water Mixing Valve
The water mixing valve allows hot and cold water to enter the tub and sometimes the solenoids within this can break down and quit working properly. It regulates three different water temperatures--hot, warm and cold--via electricity through the solenoid.
Usually only one of these solenoids fails at a time, so you will only have to replace that, which will be much cheaper than replacing the whole unit. If both solenoids fail, you will have to replace the entire water valve assembly.