AC and heater not working right

My 2011 Toyota Tacoma only has 19,000 miles and I already noticed a few little quirks with it. One annoying one is the persistent clicking noise within the AC system. It drives me nuts whenever the AC or heater is on! What can I do about this without tearing up the whole dash?
Experienced mechanics share their insights in answering this question :
Greetings! Thank you for writing in about this problem. This is a common problem with this generation of Tacoma. Toyota released a Technical Service Bulletin (TSB) and updated part numbers in late 2011. The associated TSB (T-SB-0162-11) covers the inspection and diagnosis of the malfunctioning blower motor. However, coverage under this TSB is only applicable during the 3 year/36,000 mile warranty period. Your local Toyota dealer can provide further information. If the unit is not covered under warranty, a local mechanic (like those with YourMechanic) can obtain and install a new blower motor in your vehicle.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

The blower motor controls the airflow for the heating and cooling system; it is one of the main components for the HVAC system to operate properly.
The most common reasons a Toyota Tacoma heater isn`t working are a broken heater blower motor, a problem with the thermostat, or a failed heater blower motor resistor.
Poor or Airflow from Air Vents

This will be the first and most obvious sign your blower motor has a problem. It may or may not indicate that you need a replacement motor. If there is no air or very weak airflow coming from the air vents, the motor may be clogged, or it may be malfunctioning.

In most cases, when a car`s AC fan starts making noise, it`s due to friction in the engine. This can be caused by various factors, including lack of lubrication, dirty air filters, or low coolant levels. If your car makes a rattling noise when the AC fan is on, you may have a problem with the fan blades themselves.
Problems with Your Blower Motor or Blower Motor Resistor

Without it, there`s no circulation of air—hot, cold, or otherwise. The blower motor resistor is the part that controls the fan speed of the blower motor. Both of these components can fail, resulting in the heating system simply not working.

The most common reason a Toyota Tacoma has no heat is because the heater core is bad or it has a blown fuse. Other reasons include a bad blower motor, the coolant level is low, or the water pump is faulty. The fixes only sound complicated; in reality, most of these parts are plug-and-play parts.
A faulty or broken thermostat is the most common cause of your car`s failing heat. Stuck open or stuck closed, the part can not only cause issues with your heat but also with your engine`s cooling system.
If your blower motor is experiencing some issues, you may hear a high-pitched squeal or whistling sound. You may also experience rattling and loud screeching noises. The motor blower pushes warm air out of the furnace through the ducts into your home.
The blower motor resistor controls the power to the system`s blower motor. When it fails, it can cut off all power to the motor. When the blower motor doesn`t get power, air pressure can`t be produced. You are left with a heater or air conditioner with nothing coming out of the vents.
Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.
So if you turn on your AC and hear a rattle, it may mean you have a failing or bad: AC compressor. Rattling or your car air conditioner making loud humming noises which get worse as you accelerate can both be signs you need to replace your AC compressor.
AC Loud Buzzing or Popping Noise

The issue could be tied the circuit breaker, the fan motor, or loose wiring. If it`s the circuit breaker, a common cause is dirty air filter or debris around the AC unit. For the other issues dealing with the fan motor or loose wiring, call your technician for help.

It is usually located inside the blower compartment on the side of the blower motor. Be cautious as the housing may be hot. If the button is popped up, press it down.
There are a number of things that can go wrong with your heating system, but if the air stops blowing altogether and the same is true on cold air settings, a blower motor replacement is likely in order. The good news is that it`s a fairly straight forward repair.
The most common reason for a car`s heat system not working is a lack of coolant. If your car`s heat system isn`t working, the first thing you should check is the coolant level. You can usually find the coolant reservoir in a housing near the front of the car, near the engine.
Here are some of the most common causes of why air doesn`t flow out of your vehicle`s vents: Your air intake is clogged, meaning that air isn`t getting in from the outside at all or isn`t circulating properly. There is a blown fuse in the ventilation system. Electrical issues such as a bad relay.
Your Filter`s Dirty

Your furnace needs a clean and clear air filter to circulate hot air efficiently. Over time, debris, dust, and allergens build up on these filters, which eventually causes them to clog. So if your furnace is blowing cold air, you`ll want to check your air filter.

When you turn the furnace on but no heat comes out, there may be an obstruction. Dirty air filters restrict airflow, which can make it feel like not much heated air is coming out of your vents. Check the furnace filter and replace it if its surface is covered with contaminants.
Your engine accumulates a lot of heat when working, and coolant helps to collect this generated heat by transporting it to your vehicle`s radiator for cooling. If the coolant is low and your heater is on, you may notice that your car heater only works when driving.
The blower motor is responsible for distributing warm air through the ventilation system of your living space. If the blower motor in your furnace is inadequately performing, you will hear buzzing noises when your furnace is running. This may indicate the need for a small repair, or that the entire motor is failing.
The AC Condenser Fan Motor is damaged – like the blower motor failing, a broken condenser fan motor can also create a humming noise when it breaks. If the indoor blower is working but the fan is not turning, your fan motor may emit a loud buzz. Some people perceive this noise as more of a hum than a buzz.
The location of the reset button will depend on the model of your furnace, but it can typically be found on the side of the blower motor inside the blower compartment. Once you locate the reset button, press and hold it for 30 seconds. Then, release the button and wait for 30 seconds.
Nationally, you can expect to pay about $550 on average for a blower motor replacement, including labor. However, if your unit is under warranty, you might get away with a labor-only charge of as little as $130. More complicated units, or units that are difficult to access, can cost as much as $2,000+ to replace.
If the motor is burnt out, you only have one option; to replace it. Check the coming chapter for steps on how to do it. Unless you check and replace the parts of the blower motor circuit, fixing the motor will not help. Start with those parts.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Honda Civic 2008. AC stopped working suddenly and engine check light came ON for a day.Next day AC worked and no engine light.
ANSWER : Hi there. In both cases, when an AC system is not working and a warning light is coming on the dashboard, typically a professional mechanic will complete the same initial inspection, which is to download the stored error codes that triggered the warning light initially. This tends to give them an idea as to what is causing the problems. This could be something as simple as an electrical relay that is faulty or loose or an indication of a computer related "glitch". Either way, the best way to move forward is to have a professional mobile mechanic complete a check engine light inspection.

I have a 2003 Saturn L200 2.2L Manual Drive and the heater or AC will not work no air blowing.
ANSWER : Hi there. From the description you have provided, it would appear, you have covered the bases concerning your vehicle’s inoperative blower motor. However, I am lead to believe the problem is still, no power supplied to the blower motor connector. It could be an ignition switch problem. It could be a faulty blower motor relay. I recommend having your vehicle’s inoperative blower motor be diagnosed and repaired by a certified technician from YourMechanic.

My AC does not always work. If I fiddle with the blower knob I can ususally get it to work on the lowest setting.
ANSWER : Hi There,
It sounds like you may have a faulty blower motor resistor. The highest speed setting may still work because in most cars in the highest fan speed settings the current bypasses the blower motor resistor. In some cars, if the resistor is failed, the fan may stop working completely. Another reason a blower motor resistor may fail is when the blower motor has a mechanical problem or when a foreign object jams the blower motor fan blade and prevents it from spinning freely. This leads to increased current through the resistor and causes it to overheat and fail. I would suggest having an expert from YourMechanic come to your location to diagnose your system to determine what may be causing the fan not to work properly.

My ac slowly stopped working after just two days.
ANSWER : The air conditioning system relies on a full system charge to function properly. A poorly operating air conditioning system is usually caused by a low charge from a leak. If the air conditioning compressor electronic clutch fails, the fuse blows or the relay burns out, you will notice the lack of cooling. The refrigerant inside the air conditioning system is a gas whose use and handling require a certification. Consider hiring an experienced technician like one from YourMechanic who can come out and give your vehicles air conditioning system a performance check which includes checking system pressures in an effort to offer you a more personal diagnosis.

My AC is not working took it the mechanic and he told me that’s it has a blown fuse box which is causing my AC not to work?
ANSWER : Hi there. I have not seen a fuse box fail very often on this vehicle. It is possible that he meant to say that the fuse for the AC is blown which makes a lot more sense. Most of the time when the AC fuse blows it is because the compressor is failing and has a short in the clutch.

The circuit is going to have to be tested for a short to confirm why the fuse blew. It can take some time to trace the wires, though it is probably the compressor. If you need to have this diagnosed, consider YourMechanic, as a certified mechanic can come to your home or office to inspect your AC system.

My dash board don’t work my front light work when I change my light into high beam and my back window won’t go down
ANSWER : As unfortunate as it is, your vehicle would be considered flood damaged. Diagnosing electrical problems in a flood damaged vehicle is nearly impossible. This would take many hours or even days to determine which wiring harnesses and circuits have been affected. Then nearly all of the wiring under the dash would likely require replacement as well as many sensors and switches. On a BMW vehicle, the amount of wires and switches are likely more than that of a lower end vehicle. Due to the inefficiency in cost, you would likely be able to purchase another BMW like yours for less than what it would cost to fix your car. Many insurance companies would consider this type of damage to total out the vehicle unfortuantely.

AC wont blow on max
ANSWER : Based on the information you provided for your 2010 Dodge Avenger. It is likely that you have a leak in the air conditioning system. You may also have a resistor pack going bad, or the selector switch itself could be going bad. To have the problem verified, a certified technician from YourMechanic can come to your home or office to detect any leaks and make needed repairs.

Low coolant light comes on when AC, defrost or heater is on, but only if the car is in gear and stopped, what’s wrong with my car?
ANSWER : First, you want to make sure your cooling system is full. Check the radiator not the coolant jug. And check it when it is cold. If it needs coolant, add some. Of course, I don’t feel this problem is an actual low coolant condition. I would expect to find an electrical failure in the instrument cluster or from a component or wiring harness that is connected to the instrument cluster.

As a technician, I have access to reports from technicians across the country. I could not find any reports of this problem, so diagnosing this will require an experienced tech as this is not a common problem. In addition, this happens at intermittent times making it difficult to recreate. The most challenging part of this diagnosis will be recreating the symptom. I suspect it has something to do with the brake switch circuitry because it only seems to happen when you have your foot on the brake. I would begin my diagnosis there with a wiring diagram and test light in hand. The brake switch, instrument cluster, and environmental controls all interact with each other. Something is crossed either because of a failed module or damaged wiring in a harness.

Aside from making sure the coolant is full, this will not likely leave you on the side of the road. If you take it in to be diagnosed, be prepared for them to spend more time than usual to figure it out. Since it isn’t a key problem, you may need to live with it until it completely fails making it much easier to diagnose. Either way, I do recommend having a certified mechanic diagnose the warning light to make sure there isn’t anything serious going on.

Good luck.