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Why Isn’t My Car Heater Working?

Why Isn’t My Car Heater Working? 

 

In many cases, problems with the heating system are problems with the engine’s cooling system. Therefore, most service work and diagnosis are done to the cooling system. In some cases, the heater core is the problem. In some vehicles, it is possible to make repairs to vacuum hoses and electrical connections without removing the heater assembly. If it is necessary to remove the heater assembly, the cooling system must be drained before removing the heater core. 

Heater Core

Why is my car heater not getting hot enough?

  • Air pockets in the heater core can interfere with proper coolant circulation. Air pockets form when the coolant level is low or when the cooling system is not properly filled after draining it. 
  • A gurgling noise in the heater core may be caused by a low coolant level in the cooling system. A low coolant level will allow too much air in the cooling system. The excessive air will mix with the coolant and create the gurgling noise. 
  • A restricted heater core will also cause a gurgling noise from the coolant passing through the restricted area. 
  • Coolant leaks. Internal engine coolant leakage is probable the worst-case scenario. 
  • The engine thermostat is staying open and the vehicle doesn’t reach operating temperature. 
  • Heater control valve malfunction. 
  • Blend door actuator motor malfunction. 

 

How do I fix the heater in my car? 

Problems that pertain specifically to the heater are few: the heater control valve and the heater core. Most often, if these two components are faulty, the engine’s cooling system will be negatively affected. Both items are replaced, rather than repaired

How to diagnose the cause of temperature control problems? 

When diagnosing a heating system that is inadequate, it is imperative that you follow a logical diagnostic routine: 

  • Make sure there is adequate coolant in the cooling system. 
  • Verify that the engine reaches normal operating temperature. 
  • Verify engine thermostat operation. 
  • Check if there is flow through the heater core. 
  • Check proper operation of the heater control valve. 
  • Check with a Scanner Blend Door Actuator Motor operation. 

 

How can I tell if my heater core is clogged? 

If the engine is reaching operating temperature and the heater output is not acceptable, the next step is to check to see that there is flow through the heater core. Some systems use a heater control valve .These valves may be controlled by vacuum, electricity, or a cable. Be sure that the valve changes position, allowing coolant into the heater core. If that area is good or not applicable, check the inlet and outlet temperatures or the heater hoses at the core. If one is cold, you have a restricted core. If both are hot and equal, you may have restricted fins on the outside of the core, or the blend door may not be opening to allow the blower to move air across the core. There will be some drop in outlet temperature if everything is working normally. Usually this would be 10-30 degrees. A drop more than that means the core is restricted.

How to diagnose window fogging problems in my car? 

A leaking heater core is often the cause of a windshield fogging problem. Windshield fogging is the result of hot and humid air that condenses on the cooler glass. 

A sticky film on the inside of the windshield may be caused by: 

  • A coolant leak in the heater core. 
  • Under this condition the coolant level in the radiator should be checked. 
  • A plugged air conditioning/heater case drain that allows water to collect in the case can become stagnant and produce a very pungent odor in the passenger compartment. 
Can you unclog a heater core? 

Heater cores are replaced, rather than repaired. Like the radiator, heater core tanks, tubes and fins can become clogged over time by rust, scale, and mineral deposits circulated by the coolant. Heater core failures are caused by leakage or clogging. Feel the heater inlet and outlet hoses while the engine is idling and warm with the heater temperature control on hot. If the hose downstream of the heater valve does not feel hot, the valve is not opening. 

If the heater core appears to be plugged, the inlet hose will feel hot up to the core, but the outlet hose will be cool.

How to try to unclog the heater core? 

flushing the heater core

Reverse flushing the core with a power flusher may open the blockage, but usually the core must be removed for cleaning or replacement. 

  • Check the inlet and outlet temperatures or the heater hoses at the core. If one is cold, you have a restricted core. If both are hot and equal, you may have restricted fins on the outside of the core, or the blend door may not be opening to allow the blower to move air across the core. 
  • There will be some drop in outlet temperature if everything is working normally. Usually this would be 10-30 degrees. A drop more than that means the core is restricted 

 

Cleaning a clogged evaporator/heater case drain tube often eliminates a windshield fogging problem. If the drain is clogged, a leaking heater core will allow engine coolant to accumulate in the housing. A clogged drain also allows condensed water vapor to accumulate. Both problems add moisture to the air, which tends to fog the windshield. 

What is the average cost to replace a heater core?

The average cost for heater core replacement is between $580.00 and $980.00. Labor cost will depend on the make, model, and year of the vehicle. In most cases the entire removal of the dashboard is necessary to gain access to the heater core. 

How many hours does it take to replace a heater core? 

2015 BMW 320i Sedan (F30) L4-2.0L Turbo (N20) 

The Heater core replacement labor time in this vehicle is 9.1 hrs. 

 

 

-2013 Toyota Corolla L4-1.8L  

The Heater Core replacement labor time in this vehicle is 5.2 hrs. 

 

-2010 Ford Truck F 150 2WD V8-4.6L

The Heater Core replacement labor time in this vehicle is 5.9 hrs.

 

-2010 Volkswagen Jetta Sedan (1K2) L4-2.0L DSL Turbo

The Heater Core Replacement labor time in this vehicle is 2.8 hrs. 

 

On-site automotive ac service

Why my car A/C is stuck in heat mode when the cooling mode is on?

 

A malfunctioning Temperature Blend Door Actuator Motor could be the cause. When the Winter Season begins, and you try to change the A/C settings on the Air Conditioning Climate Control from Cold air to hot air and you cannot control the air temperature.

 

What is a blend door actuator?

CALLOUT

COMPONENT NAME

2 Temperature Blend Door Actuator Motor

 

 

The blend door actuator is a small electric motor. As you adjust the temperature up and down, the signals go through the actuator to complete the request, positioning the air door on the right position.

When A/C became a popular option on vehicles in the mid to late 1970s, the systems were simple, except for some high levels vehicles, which were often the test bed of things to come.

The control systems were cable actuated, and eventually, vacuum controls were introduced. Most systems were equipped with a heater control water valve, also cable or vacuum controlled.

Automatic temperature control systems had a range of controls: vacuum, electromechanical, and pure electronic devices. They were complicated for the time and often not reliable.

MANUAL CONTROL SYSTEMS

The air delivery system controls the movement of heated and cooled air into and throughout the passenger compartment. The Hvac housing is the plenum unit located and beneath the instrument panel. It contains the evaporator and heater core, and the blower motor assembly and the blower speed control device.

The plenum houses the air doors and door actuators that direct airflow to the correct ductwork. The doors ay be controlled by cables, vacuum, or electrical actuators. Single zone systems are usually equipped with three doors:

 

The Blend Door Actuator – the blend door determines the temperature of the air flowing through the passenger compartment. If the A/C is operating, the air is dehumidified and cooled. The more air the blend door directs through the heater core, the warmer the air entering the passenger compartment.

DUAL ZONE A/C SYSTEMS

Dual zone systems operate in the same manner as single zone systems. However, most dual zone systems use two blend doors: one for the driver side and the other for the passenger side. This design allows for separate temperature settings on each side for the vehicle.

 

DIFFERENT TYPE OF ACTUATOR MOTORS

Actuator motors used in automotive Hvac systems can be one of four designs, depending on vehicle manufacturer, system design, year, and model of the vehicle:

  • Tri-state
  • Bi-directional
  • Three wire
  • Two wire

Tri-state Actuator

Temperature Blend Door Actuator Motor

CALLOUT COMPONENT NAME
2 Temperature Blend Door Actuator Motor

 

A tri-state actuator is a five-wire design. Three of the five wires are used for the feedback circuit. The other wires are for ignition voltage and Hvac control head requests.

0 volts will move the motor one way, 5 volts will drive the motor in the other direction, and when the signal wire reads 2.5 volts, the motor stops rotating.

Bi-directional Actuator Motor

Bi-directional actuators use three wires for circuit feedback. The other two wires are the positive and negative circuits that drive the motor. These circuits are controlled by the Hvac control head and move the motor direction based on the selections made at the control head.

Temperature Blend Door Actuator Motor

CALLOUT COMPONENT NAME
2 Temperature Blend Door Actuator Motor
Three Wire Actuator Motors

Three wire actuators have a power, ground, and an input wire from the Hvac control head. These actuators use a preprogrammed logic chip containing all the information to drive the motor in the requested direction. When a position change is requested by the vehicle operator, a circuit in the control head sends voltage to the actuator motor. As the motor moves, a potentiometer in the actuator compares the motor voltage to the output voltage from the control head. When both voltage readings are the same, the actuator motor stops. There is no feedback to the control head with this design.

Two Wire Actuator

Two wire blend door actuator motor

CALLOUT COMPONENT NAME
3 Temperature Blend Door Actuator Motor

 

Two Wire actuators create electrical pulses when the commutator rotates across the brushes of the motor. The Hvac control head, which has pre-programmed logic and actuator endpoint references, counts the electrical pulses as the motor moves the door through its sweep from one end to the other end. The actuator endpoints will change as the door seal wears, so if the endpoint counts become too large, a DTC will be set. If the Hvac system loses power, or if a component is replaced, the endpoints must usually be relearned through a calibration process.

SYMPTOMS OF BAD BLEND DOOR ACTUATOR

How do I know if my blend door actuator is bad?

Binding Actuators

If an actuator binds inside the Hvac plenum, the control module will attempt to overcome the restriction several times before it shuts down the circuit. You will hear the ticking noise. If the binding clears on the next activation, the control module will perform a calibration and set a history DTC.

 

What does a bad actuator sound like?

If an actuator binds inside the Hvac plenum, the control module will attempt to overcome the restriction several times before it shuts down the circuit. You will hear the ticking noise from the actuator motor.

Where is the heater blend door actuator located?

automotive dashboard

The Blend Actuator Motor is located on the Hvac Box underneath the dashboard. The exact location of the Actuator will depend on the Make, Model and Year of the vehicle serviced.

CALLOUT COMPONENT NAME
1 Left temperature actuator screws
2 Temperature blend actuator
3 Left temperature actuator lever
5 Hvac Box

Actuator motor

2015 Cadillac CTS Coupe RWD V8-6.2L SC

How do you test a blend door actuator?

Actuator diagnosis

When diagnosing Hvac actuators, always check the door for binding or restriction, caused by a distorted, worn, or damaged plenum. Check for restrictions that may be caused by a foreign object that is lodged in the door seep, or a broken crank arm on the door assembly.

Do not operate an actuator that is not attached to the door on the plenum. If the door is not attached, the motor can drive past its limits, which usually results in damage to the actuator.

What tools to use for door actuator diagnostics?

Actuator motor operation can be checked with a digital multimeter. Using service information and wiring diagrams for the vehicle, find the correct connector pins for feedback, power, and ground circuits on the actuator. Carefully back probe at the pins, taking care not to pierce the wiring insulation or cause damage to the connector pins. With the meter set on the DC volts scale, move the Hvac selector know and watch for a voltage change as the door position is commanded to change. There should be a voltage change as each position is selected.

  • Digital Multimeter
  • Service Information and Wiring diagrams
  • Scanner

These voltage readings will not give the exact position of the door. However, they will indicate that the door is moving through a complete sweep from one endpoint to the other.

How long does it take to fix a blend door actuator?

The labor time will be different depending on the make, model, and year of the vehicle and if it is a dual zone system or single. The labor will increase because of the time needed to remove all components before we can gain access to the actuator. In some model’s complete removal of the entire dashboard is needed to gain access to the Blend door actuator motor.

 

2015 Dodge or Ram Truck RAM 1500 Truck 2WD V6-3.0L DSL Turbo

Temperature blend door motor

Left side: 0.5 hours

Right side: 5.2 hours

 

2013 Ford Focus 2.0L

Temperature blend door motor replacement

Driver side: 0.5 hours

Passenger side: 0.5 hours

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
ac temperature out of the vents

How do I check the temperature of my car AC?

How do I check the temperature of my car AC?

 

 SYSTEM PERFORMANCE TEST

How do I check the temperature of my  2015 Mazda 6 AC?

1. Measure the air conditioner output temperature after approx.10 min have elapsed from engine start.

2. Place a dry-bulb thermometer in the driver-side center Vent outlet.

  1. Start the engine and warm it up.

    4. Set the fan speed to MAX HI.

    5. Turn the A/C switch on.

    6. Set to RECIRCULATE mode.

    7. Set the temperature control to MAX COLD.

    8. Set to VENT mode.

    9. Close all the doors and windows.

    10. Maintain the engine speed at 1,500 rpm.

    11. Wait until the air conditioner output temperature stabilizes.

    Stabilized condition
    – The A/C compressor repeatedly turns on and off at regular intervals.

    12. After the blower air is stabilized, read the dry-bulb thermometer.

    13. Verify the ambient temperature.

    14. Verify that the temperature reading is in the shaded zone.

 

AMBIENT TEMPERATURE CENTER VENT TEMPERATURE

41 F

39.5 F

50 F

4.5 F

59 F

41 F

68 F

42 F

77 F

43 F

86 F

43.5 F

95 F

47 F

104

50 F

 

We could easily know what should the a/c temperature be at the vents be checking this manufacturer chart. If the A/C system in the car is working properly the temperature should be near these values.

ac temperature out of the vents

How cold should my AC be at the vent in my car?

The ambient air temperature must be at least 16°C (60°F) .

Do not induce additional air flow across the front of the vehicle during the test.

 

What temperature should the A/C blow ? 

The A/C system is designed to provide the passenger compartment with low temperature and low humidity air. During periods of high heat and humidity, an A/C system will be more effective in the Recirculation mode (MAX-A/C).

We could easily know what should the A/C temperature be at the vents be checking this manufacturer chart. Taking into account  50-60 % relative humidity and an ambient air temperature of 77 F,86 F,95 F ,the discharge air temperature at the center vent should be in the range of :

50-54 F

56-60 F

63-70 F

if the A/C system in the car is working properly.

How cold should my AC be at the vent in my car?

A performance test is the best way to determine whether the system is performing up to design standards. This test also provides valuable clues as to the possible cause of trouble with the A/C system.

How do I check the temperature of my car AC?

Testing must be performed as follows:

Vehicle location Indoors or in the shade (in a well-ventilated place)
Doors Closed
Door Windows Open
Hood Open
TEMP. Max. COLD
Mode switch Front (ventilation) set
Recirculation switch Set (in-cabin recirculation ) set
Blower Max. speed test
Engine speed Idle speed
Operate the air conditioning system for 10 minutes before taking measurements

 

 

TEST READING

Recirculating-to-discharge Air Temperature Table

Inside air(Recirculation air) at blower assembly inlet  

Discharge air temperature at center vent

F

Relative humidity

%

Air temperature

F

 

50-60

77 F

  50-54

86 F

56-60

95 F

63-70

60-70

77 F

54-59

86 F

60-67

95 F

70-76

***This values are for NISSAN-DATSUN Maxima V6 3.5L***

 

ac temperature out of the vents

What temperature should the A/C blow ?

How cold should my AC be at the vent in my car?

 

The ambient air temperature must be at least 16°C (60°F) .

Do not induce additional air flow across the front of the vehicle during the test.

What temperature should the A/C blow ? 

The A/C system is designed to provide the passenger compartment with low temperature and low humidity air. During periods of high heat and humidity, an A/C system will be more effective in the Recirculation mode (MAX-A/C).

How cold should my AC be at the vent in my car?

A performance test is the best way to determine whether the system is performing up to design standards. This test also provides valuable clues as to the possible cause of trouble with the A/C system.

How do I check the temperature of my car AC?

 

1-Park the vehicle inside or in the shade.

2-Open the windows in order to ventilate the interior of the vehicle.

3-If the A/C system was operating, allow the A/C system to equalize for about 2 minutes.

Turn OFF the ignition.

4-Install the J-43600 – Acr2000 Air Conditioning Service Center ACR 2000 Air Conditioning Service Center.

5-Record the ambient air temperature and humidity.

6-Record the low and high side STATIC pressure readings.

Are both the low side and high side pressures within the specified value?

More than 16°C (60°F) – 345 kPa (50 psi)

More than 24°C (75°F) – 483 kPa (70 psi)

More than 33°C (90°F) – 690 kPa (100 psi)

How do I check the temperature of my car AC?

 

Note: Record the relative humidity and the ambient air temperature at the time of the test.

  1. Close the vehicle doors and windows.
  2. Open the driver door window 12.7–15.2 cm (5–6 in).
  3. Select the following HVAC control settings:
    • The A/C is ON.
    • The coldest temperature setting
    • The maximum blower speed
    • Recirculation mode
    • The instrument panel (I/P) outlet mode
    • All I/P outlets are OPEN.
  4. Install thermometers in the left and right center panel air outlets .
  5. Apply the parking brake.
  6. Place the transaxle/transmission in one of the following positions:
    • PARK (Automatic)
    • NEUTRAL (Manual)
  7. Start the engine and warm to operating temperature.
  8. Operate the A/C system for 5 minutes.
  9. Inspect A/C components for the following conditions:
    • Abnormal frost areas
    • Unusual noises
  10. Record the following information:
    • The panel outlet air temperatures
    • The low-side pressure
    • The high-side pressure
  11. Compare the low and high side pressures and the panel output temperatures to the A/C Performance Table below.

Does all the data recorded fall within the specified ranges of the A/C Performance Table below?

 

A/C Performance Table 2016 Chevrolet Camaro 6.2 L
Ambient Temperature Relative Humidity Low Side Service Port Pressure High Side Service Port Pressure Maximum Left Center Discharge Air Temperature
13–18°C (55–64°F) 0–100% 186–289 kPa (27–42 psi) 930–1260 kPa (135–183 psi) 10°C (50°F)
19–24°C (66–75°F) Less than 40% 186–289 kPa (27–42 psi) 909–1212 kPa (132–176 psi) 9°C (48°F)
Greater than 40% 213–323 kPa (31–47 psi) 1019–1329 kPa (148–193 psi) 13°C (55°F)
25–29°C (77–84°F) Less than 35% 220–310 kPa (32–45 psi) 1061–1288 kPa (154–187 psi) 12°C (54°F)
35–50% 241–323 kPa (35–47 psi) 1123–1322 kPa (163–192 psi) 13°C (55°F)
Greater than 50% 254–351 kPa (37–51 psi) 1157–1391 kPa (168–202 psi) 15°C (59°F)
30–35°C (86–95°F) Less than 30% 248–337 kPa (36–49 psi) 1157–1391 kPa (168–202 psi) 14°C (57°F)
30–50% 261–358 kPa (38–52 psi) 1198–1419 kPa (174–206 psi) 15°C (59°F)
Greater than 50% 282–378 kPa (41–55 psi) 1240-1460 kPa (180–212 psi) 18°C (64°F)
36–41°C (97–106°F) Less than 20% 282–365 kPa (41–53 psi) 1288–1508 kPa (187–219 psi) 17°C (63°F)
20–40% 289–378 kPa (42–55 psi) 1302–1522 kPa (189–221 psi) 18°C (64°F)
Greater than 40% 303–392 kPa (44–57 psi) 1329–1529 kPa (193–222 psi) 19°C (66°F)
42–46°C (108–115°F) Less than 20% 316–392 kPa (46–57 psi) 1419–1612 kPa (206–234 psi) 18°C (64°F)
Greater than 20% 323–406 kPa (47–59 psi) 1433–1612 kPa (208–234 psi) 20°C (68°F)
47–49°C (117–120°F) Below 30% 351–427 kPa (51–62 psi) 1529–1701 kPa (222–247 psi) 22°C (72°F)

 

School bus ac repair

Bus Air Conditioning service & repair.

BUS AIR CONDITIONING

We provide on-site A/C services for school buses in Miami-Dade County.We help you get your school bus ready for the reopening of the schools.

In-cabin air filter maintenance /replacement

Carrier Units service & repair

Thermo King Units service & repair

New hoses installation

Leaks repair

Air conditioning compressor replacement

Condenser coil replacement

Evaporator coil replacement

Give us a call for a fast & reliable service by one of our ASE certified technicians.

How can i make my car ac colder

How can i make my car ac colder

Radiator cooling fan should be working at 100 %

-RADIATOR COOLING FAN

Two fan system

One fan system

 

-FAN CLUTCH SYSTEM

AIR ACTIVATED

TEMPERATURE ACTIVATED

 

***CHECK THE FAN OPERATION BEFORE MAKING ANY REPAIR TO THE AC SYSTEM***

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

 

IMPACT OF DEBRIS ON THE AIR CONDITIONING SYSTEM PERFORMANCE

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

 

IMPACT OF AC COMPRESSOR OPERATION BECAUSE OF SLIPPING DRIVE BELT ON HVAC COMPRESSOR PULLEY 

-Check Drive Belt tension

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

 

HOW TO KNOW IF MY AC SYSTEM IS PROPERLY VACUUM AND RECHARGED.

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)

CHECKING THE A/C SYSTEM BY SENSING THE A/C LINES TEMPERATURE.

-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.