remove the actuator and theres a little knob that the actuator turns, one way is hot the other cold, it only moves a little bit, maybe a 1/2 inch worth of turning either way. so dont try to crank on it.

mine used to turn back its self so i turned the actuator to cold or hot turned the knob to match and put it back on with no screws nor plugged back in.

believe it or not, you can get a cel light from the actuator being unplugged lol happened to me before. clear it and its gone.