I bought a can of johnsens glow charge to try and find the leak but it says to recharge with the can upside down. Ive heard that rechaging as a liquid can wreck the pump. The system is empty so the pump is not running. What should I do??????

you'll have to charge the system enough to at least run the pump, and add the dye.

how do i jump the low 134a sensor on a montana 1999 to get it to pull the 134a in