I can’t get any pressure on the low side on a/c but hi side has pressure.
No pressure on low side
This is an indication of a restriction.
On a fully charged system, insufficient low-side pressure is normally the result of a restriction. A clogged orifice tube is a common cause of such problems. The high-side pressure may be elevated as the compressor attempts to force the refrigerant past the obstruction. This will quickly starve oil flow to the compressor and cause a catastrophic failure.
Source: agcauto.com