A/C System Gauge Readings
Normal Low Side
23-45 PSI
Normal High Side
150-285 PSI
Normal
Low Side
Normal Duct Temp.
35-50
Normal
High Side
Evaporator Outlet
Cold
Cold
System OK
Center Duct Temp.
Symptom(s)
Probable Solution
Normal to High
High
Warm
Poor cooling @ low speeds
Possible engine running hot
to overheating
Replace fan clutch, motor
Clean debris from condenser
& radiator. Check for bent fins
Low
Low
Warm
Poor Cooling
Low Refrigerant Charge
Repair leak evac & recharge
Low
Normal
Cold then gets Warm
Compressor runs all the time
Evaporator Fins Icing, replace
cycling switch
High
Low
Warm
Poor to no cooling,
Internal Compressor Failure
PAC-Kit time, R&R complete system
Clean flush evacuate and recharge
High
High
Warm
Poor or no Cooling
Excessive air in A/C System
System overcharge
Evac and recharge
Low To Vacuum
Normal to Low
Warm
Evap outlet warm,
Pressure equalizes slower than
Normal
Check orifice tube, if clogged
screen replace then temp drop test
condenser if excessive replace
(over a 50 degree drop)
AC system will not turn on;
No refrigerant in system
Blown Fuse
Defective switches or open wires
Check Scan Data if possible
Repair leak, evac and recharge
Replace fuse and test components for excessive resistance
Repair as needed
A/C System Gauge Readings
Normal Low Side
15-35 PSI
Normal High Side
150-285 PSI
Normal
Low Side
Normal Duct Temp.
35-50
Normal
High Side
Evaporator Outlet
Cold
Cold
System OK
Center Duct Temp.
Symptom(s)
Probable Solution
Normal to High
High
Warm
Poor cooling @ low speeds
Possible engine running hot
to overheating
Replace fan clutch, motor
Clean debris from condenser
& radiator. Check for bent fins
Normal to High
High
Warm
Poor cooling , Bubbles in
sight glass,
Refrigerant Overcharge
Evac & Recharge
Low to Vacuum
Low
Warm
Poor Cooling/Hot Receiver Drier
Low Side Restriction R&R TXV
Low
Low
Warm
Poor Cooling
Low Refrigerant Charge
Repair leak evac & recharge
Low
Low
Warm
Poor Cooling/Cool Receiver Drier
Restricted Receiver Drier R&R
Low
High
Warm
Poor Cooling/Cool Receiver Drier
R&R Condenser, large temp drop
Low
Normal
Cold then gets Warm
Compressor runs all the time
Evaporator Fins Icing, replace
cycling switch
High
Low
Warm
Poor to no cooling,
Internal Compressor Failure
PAC-Kit time, R&R complete system
Clean flush evacuate and recharge
High
High
Warm
Poor or no Cooling
TXV Stuck Open
High
High
Warm
Poor or no Cooling
Excessive Air in A/C System
AC system will not turn on;
No refrigerant in system
Blown Fuse
Defective switches or open wires
Check Scan Data if possible
Repair leak, evac and recharge
Replace fuse and test for excessive resistance
Repair as needed