Please help, my HVAC will not switch between the different settings. I guess its vaccum issue.

Also what does this mean. I assume this unit has already been switched over to R-134A. Is there a way to tell besides the sticker becauseI am ready to get this thing going.

 

 

I'm sure it's still R-12. As most people who have tried to retrofit r-134 know, r-134 doesn't work well on the small evaporator and condensors we have. The different vapor pressures and relative boiling/condensing temperatures make it less efficient than r-12. Just check the valves, if they're standard valves, it's r-12. If it's got a funky valve/fitting on top of it, it's prob a retrofit. If you have the time/money, go for r-406a. It's as (if not more) efficient than r-12, and similar ratings on environmentally friendly as r-134a. It's cost is around the same as 134, and it requires mineral oil similar to r-12 (instead of PAG)

As for the vacuum issue, like NINA said, it's probably a disconnected line. Two lines come out around the blower housing. If both are connected to a reliable vacuum source, take your HVAC pannel and see if you're getting vacuum all the way down to the selector. If you are, replace your selector (or fix it, there's a thread on here somewhere).

 

Check line from intake to one way valve to interior controls ( valve often cracks with heat or vac line gets broken while working on engine )