Air Conditioner Solution or Fix by Symptoms

This guide explains how to troubleshoot your car air conditioning system based on current conditions. 

A/C  SYMPTOMS CHART
High-pressure Low-pressure Clutch cycle times: cycle Clutch cycle times: on-time Clutch cycle times: off-time Fault cause/action
too high too high A/C compressor running constantly A/C compressor running constantly A/C compressor running constantly Air conditioning condenser contaminated
too high normal to too high A/C compressor running constantly A/C compressor running constantly A/C compressor running constantly Engine overheated
normal to too high normal A/C compressor running constantly A/C compressor running constantly A/C compressor running constantly Air or contaminants in the circuit. Too much refrigerant in the system
normal too high A/C compressor running constantly A/C compressor running constantly A/C compressor running constantly Fixed orifice tube. O-rings damaged or leaking
normal normal too slow too long or constantly normal or not at all Contaminants in the circuit or too much refrigerant oil
normal too low too slow too long too long A/C low pressure switch faulty
normal to too low too high A/C compressor running constantly A/C compressor running constantly A/C compressor running constantly A/C compressor faulty
normal to too low normal to too high A/C compressor running constantly A/C compressor running constantly A/C compressor running constantly Low-pressure line blocked
normal to too low normal too fast too short normal Evaporator blocked
normal to too low normal too fast too short normal to too long Air-conditioning condenser, fixed orifice tube or high-pressure line blocked
normal to too low normal too fast too short too short Not enough refrigerant in the system
normal to too low normal too fast too short too long Evaporator input line blocked
normal to too low too low A/C compressor running constantly A/C compressor running constantly A/C compressor running constantly Low-pressure line
- - irregular operation or inoperative irregular operation or inoperative irregular operation or inoperative A/C low-pressure switch contacts are dirty or permanently open. The connector of the A/C low-pressure switch or of the A/C compressor clutch is dirty or damaged.

 

R-134a TEMPERATURE PRESSURE CHART
Ambient Temperature Low-Pressure Gauge High-Pressure Gauge
65°F (18°C) 25-35 psi/ 172.241 kPa 135.155 psi/931-1069 kPa
70°F (21°C) 35-40 psi / 241-276 kPa 145-160 psi/1000-1103 kPa
75°F (24°C) 35-45 psi/241-310 kPa 150-170 psi /1034-1172 kPa
80°F (27 C) 40-50 psi/276-345 kPa 175-210 psi / 1207-1448 kPa
85°F (29°C) 45-55 psi/310-379 kPa 225-250 psi/1551-1724 kPa
90°F (32°C) 45-55 psi/310-379 kPa 250-270 psi / 1724-1862 kPa
95°F (35°C) 50-55 psi/345-379 kPa 275-300 psi / 1896-2068 kPa
100 F(38.C) 50-55 psi/ 345-379 kPa 315-325 psi/ 2172-2241 kPa
105°F (41°C) 50-55 psi/345-379 kPa 330-335 psi / 2275-2310 kPa
110°F(43°) 50-55 psi/345-379 kPa 340-345 psi/2344-2379 kPa