Re: 2000 Ford F250 Diesel air cond problems
 

With pneumatic actuators we apply pressure, and with a pressure above what is above the actuators spring pressure it will move. In this case its vacuum, but the same principal. With the 17-21" w.c. rating of the vacuum pump, the actuator should stroke to the full position, and remain there. With what you are describing chances are if you apply 17-21" of vacuum directly to the actuator, if it moves and stays fully stroked, it is fine. Work backwards from there until you find what is damaged or unhooked. It could be as simple as the vacuum line is disconnected or cracked at the actuator.

Sean

Re: 2000 Ford F250 Diesel air cond problems
 

Sean-- thanx got my Sat AM all set up for doing this--Regards FED 387

Re: 2000 Ford F250 Diesel air cond problems
 

OK --found it!!!! the insulatution they put around the battery over time had worn a TINY !!!!!! pin hole in the seam of the vacuum reservoir cannister--- even under water it rarely bubbled--- so I siliconed it for now but I have a BRAND NEW cannister coming--- the one we used that we thought was good had an even smaller leak but it did leak---

Thanx to all that rfesponded--- FED 387