Category: A/C system diagnosis test

ac temperature out of the vents

How the a/c should be operating in order to cool down the interior of your car

Check inside the vehicle:

  • The A/C climate control should be set to Max Cold Position.
  • A/C Climate control set button On.
  • Recirculation/fresh air mode set to recirculate.
  • Engine temperature should be in the normal range (not overheating)
  • Outside ambient temperature should be sensing outside actual ambient temperature.(Ambient temperature should be above 37 F )
  • Engine RPM’s should in the normal everyday range.
  • With the A/C  blower on Max, the mass of air coming out from the vents should be strong.
  • Cabin air Filter should be clean.
  • A/C evaporator coil should be free from debris and leaks.

Check the engine compartment :

  • The front of the vehicle should be free from any road debris.
  • The radiator and A/C condenser should be free from leaves, bugs or dirt.
  • With the A/C system ON the radiator/condenser fan assembly should be operating.
  • The Drive belt should be running all the accessories and in good condition.
  • The A/C compressor CLUTCH should be engaged with A/C ON.
  • The A/C compressor ECV should be modulating the hvac compressor output for max cold.
  • All A/C lines and hoses should be free from dye, oil ,ice or damage.
  • The A/C system should be properly charged with exact amount of refrigerant specified by the manufacturer.
  • Hvac box drain tube should be draining water from underneath the vehicle.



Learn More…

Nissan vehicle interior. Sun load sensor.

How does the sun load sensor in my car work?

Varying amounts of exposure to sunlight will modify its electrical return signal to the programmer to adjust system output toward cooler air; less sunlight will cause the programmer to adjust system output toward warmer air. Some multizone climate control systems have more than one sun load sensor.

Do you need assistance ?

Contact Us!

automotive ac compressor and refrigerant lines

Solar Sensor, Sun load sensor or Ambient light sensor.

The solar, sun load sensor, or ambient light sensor detects the heat load of the sun, elevation and azimuth. It is used to adjust the amount and direction of the cooled air through the dash vents and to control headlights operation of the vehicle.

Do you need assistance with the sun load sensor in your car ?

Contact us !

what could cause high ac compressor ratio

A high compression ratio can be caused by:

Overcharged A/C system.

Inefficient condenser.

Improper oil balance

A/C condenser insufficient air flow.

Dirty evaporator core.


Auto A/C Repair service and repair near me.AC compressor test.

We have auto ac repair mechanics near you in Miami-Dade County. Call Us today ! 

We use the best OEM and Aftermarket parts available.

How can i make my car ac colder

Problem Symptoms Table

Before replacing or repairing air conditioning components, first determine if the malfunction is due to the refrigerant charge, air flow or compressor.

Use the table below to help you find the cause of the problem. The numbers indicate the priority of the likely cause of the problem. Check each part in order.

How to Diagnose Your Car’s Air Conditioning System?

Symptom Suspect area
No blower operation 1.       Blower fuse
2.       Blower relay
3.       Blower motor
4.       Blower motor resistor
5.       Blower speed control switch
6.       Wire harness

No air temperature control

1.       Engine coolant capacity
2.       Heater control assembly
3.       Temp actuator
No compressor operation 1.       Refrigerant capacity
2.       A/C fuse
3.       Compressor
4.       A/C pressure transducer
5.       A/C pressure switch
6.       Evaporator temperature sensor
7.       Wire harness
No cool comes out 1.       Refrigerant capacity
2.       Refrigerant pressure
3.       Drive belt
4.       Compressor
5.       A/C pressure transducer
6.       Evaporator temperature sensor
7.       A/C switch
8.       Heater control assembly
9.       Wire harness
Insufficient cooling 10.   Temperature actuator
1.       Refrigerant capacity
2.       Drive belt
3.       Compressor
4.       Condenser
5.       Expansion valve
6.       Evaporator
7.       Refrigerant lines
  8.       A/C pressure transducer
9.       Heater control assembly
No engine idle-up when A/C switch ON 1.       Engine ECM
2.       Wire harness
No air inlet control 1.       Heater control assembly
2.       Intake actuator
No mode control 1.       Heater control assembly
2.       Mode actuator
3.       Intake actuator
No cooling fan operation 1.       Cooling fan fuse
2.       Fan motor
3.       Engine ECM
4.       Wire harness


How can i make my car ac colder

How can i make my car ac colder

Radiator cooling fan should be working at 100 %


Two fan system

One fan system





The radiator fan(s) should be on any time the A/C is on.


Road debris affect the heat transfer of heat exchangers in your vehicle and the overall capacity of the air conditioning.

Clean all the road debris outside the car

(on the windshield)

(on the condenser coil)

Clean all the debris inside the car

In cabin air conditioning filter

Evaporator core

Screen air inlet


-Check Drive Belt tension

An excessively loose drive belt will negatively impact the air conditioning compressor capacity.


Check refrigerant charge with gauges (You need special hvac equipment and EPA certifications)

Check refrigerant charge by sensing A/C lines temperature (Do it yourself)


-Open the hood to get access to the engine compartment (Be aware of all moving parts and hot components)

-Start the engine up.

-Set the A/C Climate control for Maximum blower speed position.

-Set the A/C Climate control for Maximum cold temperature position.

-Let the A/C system run for 5 -10 minutes.

-On the engine compartment identify the A/C lines.

-The Liquid line should be warm to cool even in a hot day

. (A liquid line cold or hot indicates a problem)

-The Suction Line should be cold

. Heavy frost or excessive moisture condensation on the Suction Line indicates a problem.

. Ambient temperature or too hot Suction Line indicates a problem.

-There should be a Temperature difference (TD) between the Liquid Line and the Suction Line (Check temperature before the Metering Device)

If the temperature of both lines is the same, it indicates a problem in the A/C system:

1-Compressor not pumping.

2-Compressor not turning on.

3-Low on refrigerant.

motor vehicle repair near me

Blower motor only start working after I hit a bump.

In most cases that is a sign of worn down blower motor brushes not making a good contact. In some cases the blower motor/resistor pigtail could cause erratic operation of the blower motor too.

What is a blower motor?

The blower motor is a simple squirrel cage type of fan, DC electrical motor. It is located underneath the dash, usually inside the hvac case. Depending on the vehicle, there could be more than one blower motor

What is the function of the blower motor?

Ram air flowing through the evaporator does not provide enough air flow inside the vehicle for cooling purposes so the blower motor forces air past the evaporator and the heater core and out of the vents.

What are the main causes of a blower motor failure?

Noise from the blower motor due to a bad bearing or debris in the fan. A restriction in the cabin air filter that causes internal failure of the blower electrical parts and poor grounds are the main causes of failure and replacement of this air conditioning component.

Car A/C Blower motor service and repair

Call Us Today !

We have ASE certified auto a/c repair mechanics near you ready to service and replace the blower motor in your car.


What causes an ac compressor to lock up

What causes an ac compressor to lock up

Inaccurate refrigerant(freon) charges increase the chances of auto ac compressor lock up. Modern auto a/c systems require super accurate charging. Being off as little as 2 ounces can cause problems.R-134a and R-1234yf ac system tolerances require charge rates that must remain or should be charged within +/- 5% of OEM recommendation. SAE J2788 requires charge accuracy of +/- one-half ounce.

Attempting to charge by cans is History !!

Car ac compressor lock up due to improper compressor lubrication.

Refrigerant moves the oil inside the ac system and helps to cool down the ac compressor. An undercharge or overcharge refrigerant condition will increase the air conditioning compressor temperature and a change in oil viscosity and lubrication characteristics. Most compressor lock ups are the result of a lubrication problem.

AC compressors lock up due to ac system contamination

Auto ac compressor damage may occur because of system contamination. Anything more than the correct type of freon and oil is a contaminant. The use of sealers to fix small refrigerant leaks will cause oil and refrigerant contamination and ultimately ac compressor lock up. Sealer can’t be removed from the A/C systems. The contaminated components must be replaced.

The use of excessive Dye to help finding leaks in the ac system could create a contamination problem as well, increasing the normal working pressure of the ac compressor and the overall efficiency of the air conditioning system.

Improperly replacing any component in the automotive air conditioning system where the system must be opened for replacement of the damaged part and not evacuating the system before recharging it with the proper amount and type of refrigerant will contaminate the ac system with air. Air and moisture inside the system will create excessively high operating pressures and temperatures and eventually could lead to a compressor lock up.

Inefficient ac condensers and air conditioning compressor lock up

Debris on the condenser will affect the desuperheat, condensation and subcooling processes happening in the auto ac condenser.AC condenser with bent or missing fins will be unable to efficiently operate. An inefficient ac condenser will cause an auto ac compressor to lock up.

Low Refrigerant charge and electronically controlled compressor lock up ?

The car engines in vehicles with the clutchless compressors should not be run without refrigerant in the A/C system. Without refrigerant to move the oil, the auto ac compressor may not be properly lubricated and compressor lock up may result.

Do you need assistance inspecting the state of your ac compressor in your vehicle?

Call Us today ! We have automotive ac specialists near you.