Car HVAC System Replacement

How Does A Car HVAC System Work?

Located near your car’s radiator is a condenser. That condenser is part of a closed system in which refrigerant is constantly being pumped through many different parts. The condenser is the end and the beginning of the air cooling process. Its blower will cool the refrigerant in the system with air flowing through the front grille of the car. It then flows through the evaporator (which is similar to a radiator). By the time the refrigerant is to the evaporator, it has been chilled. Your cabin air fan blows air through the evaporator, which cools the air. The air then goes into the cabin of your car.

The heating system uses a heater core, which is also similar to a radiator. Hot coolant from the engine circulates through the heater core. The cabin air fan blows air through the heater core into the cabin.

Why Is Your Car's HVAC Blower Not Working?

There are many components involved in operating a car’s HVAC blower, which means there can be several reasons why it doesn’t work. Starting with the fuse box, the fuse completes the electrical circuit required to power the blower. From there, cables connect the blower motor to the car battery, and to the switch that controls the blower.

The reason your blower doesn’t work could be because of a blown fuse, a bad wire, a bad switch, or a broken blower motor. To diagnose which of those components may be the problem, use your car’s schematics to find the parts of the system and test each of them individually.

How To Clean A Vehicle Air Conditioning System?

There can be many nasty things lurking in your air conditioning system. You must find your car’s A/C Condensation drain tube, which is usually located directly above the spot under your car where water drips while the air conditioning is on. That tube leads directly behind the blower. You can spray off-the-shelf disinfectant or cleaner foam into that tube and let it sit for a few minutes. The next time you run the A/C, the condensation will rinse out the cleaner and the crud.

You can also replace the cabin air filter and clear out leaves or other debris to solve any issues you may have. Oftentimes moldy or old cabin air filters will cause more issues than you may think.

Why Is Your Vehicle's A/C Not Working?

Many things can cause car A/C to stop working. If your system is blowing white vapor it could be excess water filling your heater box because of a clogged drain tube. A whistling or hissing sound could be a refrigerant leak that needs to be addressed. Sometimes the A/C might only work intermittently. That can be a sign of a control system failure. If the A/C only works while you’re driving, and the air doesn't get as cold as normal, that can be a sign of a refrigerant leak. (By the way, we talk about other electrical parts not working on the ISS blog. If you're struggling with a CUE radio or instrument cluster, take a look.)