its on the driver side bolt of the driver side fan on teh radiator. there're two relays. one is the compressor and one is the fan. i forgot which one is which.
but if ur a/c fan works, then a good way to test it is by switching the relays.
switch the put the compressor plug in the fan realy and viceversa.

it'll tell u if its the relay thats really bad. mine was a pain in ass. u have no idea what i didn't do to figure out what it was. at the end i gave up and took it to an electrician and all he did was jumped two wires coming out of the ecu. and charged my 110 bucks (thats why i didnt wanna go there in the first place)

but later on i replaced my ecu and removed teh jumper and it worked fine.

few months later the thin circuit wires on the chip board of a/c control unit blew up.
i fixed those by rewiring them. its been working fine since, been more than an year already.

and by the way, my relays were blown too.