Low pressure port on AC system read too high; compressor won't come on

my AC on a 2000 Nissan frontier has excessive pressure on the low pressure side . The compressor is also not coming on. Is there a high pressure switch that comes on the cuts power to the compressor if there is excessive pressure ? Should I drain some refrigerant from the system to bring the pressure down. I don’t think the expansion valve is the problem, because there is excessive pressure even when the system is off. Perhaps the previous owner overcharged it