I should clarify this a bit. The ammeter will show load, but the system has to be fully charged and superheat correct. Depending on if it is a orifice or TXV or electronic metering valve. First charge to the correct suction pressure in cooling if amp's are low. Then check for valve problems by manually jumping it to heat as you watch your gauges and feel the discharge of the valve to the evaporator..
I found all 4 ports too close to the same temperature. When shifting the valve no pressure changes. After scratching my head for a second I thought to pinch the discharge line and start the unit, amp draw and discharge pressure rocketed. Change the reversing valve and back to normal. ??