Can anyone recommend a book that'll teach me basic auto A/C repair procedures e.g. how to evacuate the system and recharge it? I figure the required equipment won't cost much more than I'd pay a shop to do the work. This is for my Chrysler van, not my xB, but IMO it's not really off-topic because Scions also have A/C.

you have to get certification to work on an ac system the machine is not cheap. plus your are then taking the responsibilty of properly disposing of a hazordus waste chemical.

Well, I know I don't need certification to buy R-134A, unlike R-12. And there apparently isn't much refrigerant left in the system, because it won't stay running long enough to suck in refrigerant though the low-side port. So I'm not entirely convinced that I'd be doing anything illegal by letting out what's left, and then evacuating the system and putting in a new charge.

Since you don't know whats left in the system, and apparently don't know how to work on the system, you don't know now much you are letting out.

I can get you the manuals, but I am not going to assist you in this illegal pollution. Take it to someone who knows what they are doing.

[gets off soapbox]