90 cavalier,a/c issue

i have a 90 with the 2.2 tbi. i just replaced the a/c compressor since the old one had a leak and recharged the system. now my issue is that i can turn the a/c on and then the motor starts reving and the coolent fan starts turning on and off. i checked the a/c relay and its click on off on off like that. if i remove the relay then fan turns off and motor idles correctly. now once the a/c compressor kicks in then it idles correctly and the fan runs at full speed as it should. it did this even before the new compressor. during this i watched the pressure in the a/c system and it never drops low. what woulds cause this to happen and i've also tried replacing the relay.

also does anyone know where the diode is for the a/c compressor clutch?