The thermostat is responsible for regulating the temperature of the AC system. If the thermostat is not working properly, it won't be able to regulate the temperature properly, which will cause warm air to be blown into your car.
A bad thermostat could certainly cause the ac not to work. You can check the t'stat by removing it from the wall and jump the red wire to the yellow (R to Y) at the wall plate. That should cause the outdoor ac to run. If it does run then the t'stat is bad.
Temperature Fluctuations: One of the most common signs of a bad thermostat is erratic temperature readings on your dashboard gauge. If you notice that the temperature gauge moves from normal to hot quickly or fluctuates unexpectedly, it's a clear indication that your thermostat may be malfunctioning.
The compressor is the core, primary part of every A/C system. They control temperature output with an electrically operated clutch. This clutch turns on and off whenever you change the temperature or if the HVAC module senses it has reached the desired temperature.
Sounds a touch dramatic, but we want to make a point about how important your home's thermostat is for the overall operation of your HVAC system. The thermostat affects comfort, energy consumption, and the health of the AC and heater.
Your thermostat reads the temperature of the room, then sends an on or off signal to the air conditioner. The AC itself isn't detecting the temperature in your home, so it has to rely on the thermostat.
Why is my car air conditioner not blowing cold air? There can be a number of reasons why you can air conditioning is not blowing cold air. The most common reasons could be a clogged filter, cooling fan problem, radiator trouble, or it could simply be that you need to recharge (regas) your air conditioning.
A thermostat is responsible for turning on and off the air conditioner's compressor and fan. The thermostat senses indoor temperatures and uses this data to determine when the rest of the HVAC system needs to run and when to stop; i.e. it's a switch connected to a temperature sensor.
Thermostat: The thermostat regulates the flow of coolant into the engine keeping it at its optimum operating temperature. The thermostat is closed when the engine is cold. As the engine heats up, the thermostat opens and allows coolant from the radiator to circulate.
The average cost for car thermostat replacement is $661 to $747. Enter your vehicle's information to see how much thermostat replacement costs in your local area.
If you drive with a bad thermostat, your car could overheat, causing severe and expensive engine damage. And while it's technically possible to drive without a thermostat, we don't recommend it. Your car will not reach an acceptable operating temperature, resulting in higher fuel consumption and excessive engine wear.
A malfunctioning thermostat will have trouble keeping your home's temperature at the right setting. If there's something wrong with the motherboard, it may change its own settings at random. You can test the thermostat by lowering the settings to see if the problem persists.
Any time you are having an issue with heating and cooling units, such as after a sudden power failure or after your children have had 'control' of the system while you've been away, resetting the thermostat should be the first thing you try when attempting to rectify HVAC system issues.
If your AC is cold but not cold:
Check to see that the cooling fans on the condenser or radiator are running when the air conditioning is on. Look for any restrictions like leaves, bugs, or dirt that could be preventing air from passing over the condenser. Check the cabin air filter to make sure it's not clogged.
If you find your car A/C not cooling in hot weather, it could be due to a leak in your system, a faulty condenser, or a broken compressor.
Signs of a Faulty Thermostat
AC Refuses to Start or Stops Suddenly: A thermostat that's not working correctly might fail to initiate the cooling cycle or might randomly shut off the AC. This erratic behavior can be due to electrical issues or miscommunication with the AC unit.
The standard thermostat is hardwired to communicate with the furnace, air conditioner and/or the heat pump. Typically, a home thermostat utilizes five wires that connect to HVAC components and power. These wires are color-coded for easy identification.
One of the most obvious signs that your vehicle needs a Freon recharge is that your vehicle will be blowing warm air, even after your vehicle has been running for some time. If your refrigerant gets too low, there will simply not be enough “coolant” to cool the air as it is passed through your evaporator coil.
An AC leak will lead to warmer air from your vents over time. In most cases this can be fixed with a proven stop leak additive to seal up any leaks. When it's time for an AC recharge, turn to AutoZone.
AC repair costs can vary widely, depending on the cause of the problem and the type of vehicle. On average, car AC repair costs run between about $430 and $520. However, if you need a new compressor, you can expect to spend $1,300 to $2,500 or more.