Why is my 1996 blazer AC compressor not disengaging?

My ac system was recently replaced (compressor, pressure hoses,
accumulator, and orifice tube), but now the new compressor will not
disengage. This is resulting in my car overheating (because the compressor
isn't cycling) and me not being able to turn the heat on (If I turn my climate
controls to the hottest selection, the AC is still going and my system is
kicking out cold air). I believe that the clutch for my ac is bad, so if you have
any advice for fixing that (should I start with wiring or the ac compressor
itself). or any tips on other ways to keep my engine cool, I'd appreciate it!