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AUTOMOTIVE AIR CONDITIONING
TROUBLE SHOOTING GUIDE
INTERPRETATION OF GAUGE READINGS
Below find a list of possible gauge readings and what they mean.
Highlow side and low high side readings. Your compressor is bad. The closer together the readings are, the less efficient the compressor is.
Low side into vacuum, high side normal. Expansion valve stuck in closed position, clogged with debris or restriction in the liquid line.
High low side, normal high side. Expansion valve stuck open. Hot water valve (heater control valve) trickling hot water into heater core causing AC plenum to get warm. Open seam on evaporator case drawing hot air from engine compartment. Bad condenser fan. Bad fan clutch. Too much oil in system. Possible overcharge and what appears to be a normal high side is actually too high.
High low side, high high side. Overcharge. Dirty condenser fins. Problems with cooling system, condenser fan(s), or radiator fan clutch. Restriction in condenser. Clogged drier.
Normal low side, high high side. Restriction in condenser. Overcharge. Clogged drier.
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