Why does my Frigidaire Heavy duty laundry center only wash on delicate

This can happen when the cable to the controller becomes partially loosened. Id get into the back and make sure all the connectors are fully plugged in.

Selector switch

If your washer has a selector switch on the control panel, make sure the button for your selection is pressed all the way in, or set properly.

Drive motor

Many washing machines have multiple-speed drive motors. Though it's uncommon, the drive motor may work fine on one speed but not on another. If the drive motor has failed on one speed, you need to replace the entire motor.