Let me get this right,

1. It had a leak, as in it's fixed?
2. Why are you looking for a pressure switch?

This is what I would do, since I too cannot afford mechanics working
on my a/c system.

I would rent an evacuator, maybe rent a r134a manafold if I could(but
can be bought for about 80 bucks).  Buy a few cans of r134a(5 bucks
each have about 3 ready), research normal system pressures(to be anal
for specific ambient temps).

Hook up the evac to the manafold, and hook up the manafold to the
system, high and low.  Hold vaccum for an hour at 29".  Then charge
r134a with system off till pressure is high enough to close the low
pressure switch.  Then start engine, watch system pressures(if a/c
came on, if not troubshoot why), and charge as necessary.

Now that is me, I've done my own ac work after I got pissed about how
much a leaking schrader valve cost me to get fixed by a shop.  Man,
they charged me for the time the car sat there doing nothing during
the hold period.  ugg. sorry off track.

Now sounds like something you can do?  IMHO no one should ever work on
an a/c system without propertraining and experience.  Liquidized gas
can be dangerous, and hoses hanging around a running engine can ber
dangerious as well.

hth,

tom

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