I have had a problem with a tac 20 where the unit was shut down over the weekend. the oil gets cold and the motor ran until the low oil timer tripped on the restart. it took a while but I had to keep running the motor until the oil reached the proper temp. then it took off and ran. The valve kept bypassing until the oil got warm.

What type of jacks do you have? Find it tripped out on the low oil time, sometimes you need to do a hard sync on the twin posts. Not doing the hard sync the unit will run visc and never stop.

You got a bad thermo. Active low means 0 volts or active g24 on that particular input and thats what you got right now. Just lift the wire off the input term...SBR has a great point if it holeless those can be notorious for trying to resync but they will eventually fault out with a resync fault. A hard resync is to pull the buffer stands out and manually lower the car down this evens out the pressure on each jack which reseats the check valves in the pistons. Good luck...Oh the over temp sw. Is normally closed and the oil temp set is normally open when the oil is perfectly warm.

Thanks Guys - ill check it out