I recently picked up a hydro fit that is stuck on phase 1 building fire panel is reset and 3rd party devices check good normally closed the print shows. I checked the fs key switch and have good continuity. But the Phase 1 signal seems as high. Cleared pf ram tried Power off reset tried resetting cpu. Even. Unplugged the wires coming back to the controller. Any ideas what might cause it to lock up?

Did you try removing the wires from the modules going to the hydrofit board and just put jumpers on them? That will determine if it's the fs modules or a controller problem

Are you getting DOL at the main recall floor?

Ended up just clearing the pf and SAC ram again and the car went back into service.

Glad you were able to get it back up and running. I don't have alot of experience using the blue tool.