Find the pressure switch at the receiver drier and WITH THE ENGINE OFF remove the connector and short the pins at the connector while ignition is on AND ENGINE OFF. You should here the clutch click. If not, troubleshoot the electrical problem until it does. ALSO WITH THE ENGINE OFF, turn the forward most plate on the compressor by hand to ensure that the compressor rotates freely with no metallic feel, you will only feel smooth compression pulses.

THEN use correct manifold gauges to check your charge. Don't use a suicide hose. On any system you SHOULD check high side pressure, but on a converted system it is IMPERATIVE that you monitor high side pressure.

Good luck,