My AC Compressor will not shut off. on 1999 Ford Escort

We have replaced the high pressure switch and the relay module. The problem started with the AC not blowing cold air, just air from outside. Now, the air works, but when the dial is in the AC position, the compressor will not shut off every so often like it's suppose to. When the dial is turned to off, the compressor goes off, just in the AC position it never turns off. Does anyone know if its the switch or the module that's bad? or another problem with a different part? Thanks!!

by in Easton, MO on April 05, 2012
3 answers
ANSWER by , April 06, 2012
The system uses a clutch cycling switch that cuts it off when low side pressure dip to a predetermined pressure. It cuts off to prevent evaporator freeze up. On a hot day the compressor may not cycle but on a cool day it may cycle often. System pressures need to be checked before any thing is replaced.
ANSWER by , April 06, 2012
something is sticking maby the relay are the compressor switch is bad
ANSWER by , April 06, 2012
you may also have an bad on /off switch on knob