A/C blows hot air, compressor clutch not disengaging when turning off the A/C

When we turn on the A/C, the compressor clutch engages, but the pressure in the two pressure lines don’t change. However, when we turn off the A/C the compressor clutch doesn’t disengage. Also, the blower fans turn on and off accordingly. The lines have plenty of coolant in them and they are pressurized, they just won’t change in pressure when we turn on the A/C.