Why does the AC light turn on but not cool when pressed?

[ClaraLynn]

Air conditioner malfunction or power outage may cause the AC not to cool. Below is relevant information about automotive air conditioning: 1. Introduction to Automotive Air Conditioning: The automotive air conditioning system consists of a compressor, condenser, throttle element, evaporator, fan, and necessary control components. It is designed to regulate the temperature and humidity inside the vehicle, providing a comfortable environment for the driver. 2. Working Principle: When the compressor operates, it draws in low-temperature, low-pressure gaseous refrigerant from the evaporator. After compression, the temperature and pressure of the refrigerant increase, and it is sent to the condenser. Inside the condenser, the high-temperature, high-pressure gaseous refrigerant transfers heat to the outside air passing through the condenser and liquefies into a liquid. When the liquid refrigerant flows through the throttle device, its temperature and pressure decrease, and it enters the evaporator. Inside the evaporator, the low-temperature, low-pressure liquid refrigerant absorbs heat from the cabin air passing through the evaporator and evaporates into a gas. The gas is then drawn into the compressor again for the next cycle.

[Riley]

Recently, my old car has been acting the same way. When I press the AC button, the light comes on but the air blowing out isn't cold at all. It's really uncomfortable driving in the summer. I think the most likely issue is insufficient refrigerant, possibly due to a leak in the pipes or poor system maintenance. Alternatively, there might be a problem with the compressor, like a faulty clutch preventing it from starting. Last time I got it repaired, the mechanic mentioned that the fan not spinning could also be the culprit—check if the interior fan is running properly. No sound means no cooling. For safety's sake, don't delay; take it to a professional shop right away to prevent the problem from escalating and costing more. I once thought it was a minor issue, but it turned out the compressor bearings were rusted and damaged, costing over a thousand to replace. Regular maintenance really saves a lot of hassle—don't wait until it breaks down to take action.

[McSavannah]

I used to tinker with minor issues in my car and encountered a situation where the AC light was on but it wasn't cooling. I suspect this often happens in the refrigeration cycle, either due to refrigerant leakage or a clogged evaporator. The compressor might also fail to start because of a clutch malfunction or a loose belt. The light being on indicates that the electrical circuit is intact, but if the compressor isn't running, check the fuse box to see if the relevant fuse is blown. Try listening for a humming sound in the engine compartment when you turn on the AC. If there's no sound, go ahead and replace the relay or relay socket—it's quite inexpensive. Regular maintenance, like adding refrigerant and testing pressure, can prevent such issues. Otherwise, a long-term refrigerant leak in the system not only results in poor cooling but also damages other components, leading to more expensive and troublesome repairs. Remember not to force the AC on under scorching sunlight, as it can easily lead to heatstroke.

[LaBrody]

My car had this issue before - the AC button light was on but no cooling at all. The problem could be something simple like low refrigerant level, or a broken compressor. I suggest first checking if the blower fan is working normally. If it's working but still not cold, most likely the refrigerant has leaked out and just needs a refill. Other possibilities include a frosted evaporator or faulty sensors, but don't attempt DIY repairs. The safest approach is to take it to a professional repair shop where they can check electrical leaks and pressure values with proper equipment. Don't neglect regular maintenance - my friend delayed repairs until his compressor got completely ruined. Driving without AC in summer can be dangerously uncomfortable, so don't try to save those small repair costs.