Match the symptom, then work through the safe checks.
1. What best matches what you observe?
2. Complete only the checks that are safe for you.
Show stop conditions
- A belt squeals or smoke appears
- You hear grinding from the compressor area
- You plan to vent or handle refrigerant without proper equipment
Likely causes
- Refrigerant is low because of a leak
- Compressor is not engaging or being commanded
- Condenser airflow is poor
- A blend door or cabin filter is restricting cold airflow
Quick checks, in order
Compare vents and settings
Use maximum cooling, recirculation, and medium fan speed. Check whether one side is colder.
Check cabin airflow
Weak airflow can point to a clogged cabin filter or blower issue rather than refrigeration.
Observe radiator fans
With the vehicle safely parked, note whether cooling fans operate when AC is requested. Keep clear of moving parts.
Book leak and pressure testing
Refrigerant should not be repeatedly topped up without finding the leak.
How does the cooling behave?
Condenser airflow or cooling-fan operation is a likely area to inspect.
A dual-zone setting, blend-door actuator, sensor, or refrigerant distribution issue may be involved.
Check the cabin filter, blower, and air path before focusing on refrigerant.
Stop and get qualified help when
- A belt squeals or smoke appears
- You hear grinding from the compressor area
- You plan to vent or handle refrigerant without proper equipment
Frequently asked questions
Can I just add refrigerant?
Loss of refrigerant usually means a leak. Correct diagnosis includes leak testing and charging by specification.
Why is AC colder while driving?
Vehicle speed increases airflow through the condenser, which can mask a weak or nonworking cooling fan.