[QUOTE=pberku;1505489]Arthur, I just topped up my AC system with 1 can (12 oz) of R134. Most of the bubbles are gone, but fan still didn't come on. Then again the ambient temperature is only 18 C (65F). So its probably to cold. I'll wait for a warmer day.>>

OK. Now you prob just need some ambient temp.
As you can see, there is a very fine line between the requirements for aux fans to get triggered ..the reason for this is they do not want to have to use the fans until there is a High Thermal Load condition.. that's all they are there for .. as an aux aid to the system when needed. I am confident you will prob find them to trigger on a hot day .specially at idle in the same spot for a few minutes...
I do want to say that the correct way to really check this out is with gauges to monitor the high side , but for the diy guys here, I know they do not have the proper equipment , so I do post with that consideration in my BarnYard techniques ..but they work.
Anyway, this fine line for fan cut-in is so fine that many times one can add as little a 2 ounches of refrigerant and get the high side back to fan cut-in specs..but the ambients needs to be there before doing so...[some guys put cardboard in front of condensor the simulate that condition, but they know what they are looking for , so i don't recommend that for you.].wait for a hot day..you will see.

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Yes , it is true..they are factory sealed into the line...
The reason I mentioned for you to give yours a quick jab is b.c when a tech is removing the test lines and tap from a valve , it does not get that quick Snap action to seal it..it is quite common.. the reasoning behind this is that the sealing off of the valve is actually done by the pressure from inside the system pushing the valve closed ..by snapping it shut, it seems to immediately seal from it's seating better than if it is slowly released , which is what happens when the charge line tool is taken off/removed. I always snap them shut.. even a few little taps on the side will help seat one that is not completely closed...and then make sure the cap is tight , even though the caps funtion is a dirt cap, not a pressure seal..