the resistor in the box gets cloged with leaves .i just had mine regassed with the old gass its heaps cooler and if i have to refit the system i might get the whole system of a ED they use the new gass standard have to change everything even the climate control works a different way .

i went for a drive with my mate in his vn...the a/c in his car is sooo much better than mine but his car is fadded sky blue...mines hertiage green...so could be the darkness of my colour...
but still..i want freezing a/c!

if your air cond is not as cold as it should be- esp at idle- try
pressure cleaning the condenser to get rid of any leaves and gunk.
Its a small looking radiator thingy infront of your normal radiator
and transmission coller (auto's). Also make sure you have a
fresh receiver/dryer (filter). about $22-. A very common prob
with most fords (88 to Au111) is if the refrigerant level drops
even slightly the click in solanoid on the compresser wont click on.
(A safety thing to stop you blowing seals/bearings ect.... ) on the
compresser. If your refrigerant (gas) level is low its most likely
....but not always a leak from your evaperator witch is up under
your dash next to your heater core. Best to replace both at the
same time. Not cheap- about 5 hours labour at the auto electricions-
but a c##t of a job if you do it yourself. (dash has to come out)
Hope this helps.

By the sounds of it the evaporator may have failed, when they regased your car did the mechanic put Dye check into the system ???, if so take it back and have him check the drain out let with a black light, this will show up leaking gas,