The problem you have with the T handles is, they are 20 years old and YES, odds are you will break them off if you force them. The sensing unit ONLY affects Auto level operation. You can still manually extend all 4 jacks. IF you state, that after messing with the control box, another(3rd) jack started working, then that points to a corroded connections at that box. IF you determine that the control box is defective, you will have to send it back to HWH for rebuild. They no longer make or stock that control box. The usual diag is to check EACH jack solenoid for ground and 12 volts AT the solenoid when operating the jacks. EACH jack should have power and ground. Then you go from there. The LINK I sent you gives the Diag sequence. Doug
