LEXUS AIR CONDITIONING SYSTEM

Lexus Air Conditioning System Diagnosis

              Normal Operation· 

The compressor pressurizes the refrigerant into a high pressure hot gas. The condenser removes heat from the refrigerant gas, turning it into a warm liquid. 

· The cooling fan provides air flow to assist in removing heat

· The filter/drier (or receiver-drier in some vehicles) filters impurities and water from liquid refrigerant.. 

· A small opening in the expansion valve allows high-pressure liquid refrigerant to escape into the low-pressure side of the system. As it does, it expands, becoming a cool mist. 

· The blower motor blows air across the evaporator where heat from the air converts the refrigerant droplets into gas. This absorbs heat and cools the air. 

· The refrigerant and absorbed heat return to the compressor to repeat the cycle.

A.C FLOW SYSTEM DIAGRAM

Low Charge Symptoms:

• Poor cooling, no cooling at all 

• Low side below normal 

• High side below normal 

• Air bubbles in sight glass (when equipped with a sight glass)

Overcharged Symptoms:

• Poor cooling 

• Low side above normal 

• High side above normal 

• No air bubbles in sight glass (when equipped with a sight glass)

Compressor Failure Symptoms:

• No cooling at all 

• Low side above normal 

• High side below normal 

• No air bubbles in sight glass (when equipped with a sight glass) 

 

Moisture in System Symptoms:

 • Intermittent poor cooling 

• Low side at vacuum intermittently 

• High side below normal intermittently 

• Pressures are normal for a while, then below normal for a while. 

• Air is cool when pressures are normal, then not very cool when pressures drop.

Restriction in Condenser Symptoms:

• Poor cooling 

• Low side below normal 

• High side below normal 

• Frost or dew on tubing from condenser...