alright, I just went through three days worth of work replacing the evaporator, condenser and compressor on my 2003 V40.
I figured all the hard work was done and prepared to recharge the system.
1) I pulled vacuum for 30min - check (30inHG)
2) I let the vehicle sit for 45 min to make sure vacuum held - check (30inHG)
3) I vacuumed pump the system for 90min to remove all humidity - check
4) I ATTEMPTED to start loading R134a cans via the low pressure port...no dice!

Important notes:
1) I closed off the high pressure port at the service port on the vehicle

When I connect the pierced can of R134a to the yellow hose, open up the blue gauge (counterclockwise) on the manifold gauge and open up the blue gauge at the low pressure service port (clockwise) all I get is steadily building pressure, with no weight change to the can of R134a. WTF???

To make things even more confusing, it looks like the system may have taken a partial charge (maybe 100g at most) and just enough to get the compressor coming on. The thing is, it's not cycling on and off like you would expect it to at low refrigerant levels. Instead it pretty much stays on. If that weren't weird enough, the AC condenser fan does NOT turn on when the compressor does. Pretty sure they always turn on at the same time.

I tried switching the AC fan relay with the horn relay to see if that would make a difference....no dice.

Any AC experts out there who could weight in?

 

Gave up and took it to professionals who had no trouble refilling. Should have done that to begin with. No more diy refills for me.

 

Those gauges and the associated valves / connections / hoses can be confusing - some of the "connections" are just blanks to keep a hose attached. I will normally just fill the system with an el cheapo low-side-only gauge / filler. Monitoring the high pressure side is kind of cool (pardon the pun) but if the problem is just low gas, I'm fine with just filling it while monitoring the dash vent temperatures and the low-side pressure. Not much to go wrong with that process...

 

the only trick I've used when filling from the low side is to jumper the low pressure sensor to allow the compressor to engage while you have the cannister attached.