The condenser fan relay allows the cooling fan to pull air through the radiator and the condenser to cool the vehicle. This part is connected to the condenser fan and is normally used when the air conditioner in the vehicle is turned on. Other parts of the condenser fan relay include the fan motor, control module, and temperature sensor. Together, these all make up a circuit that allows the vehicle to be cooled.
The condenser fan relay is the part of the circuit that is most likely to fail. A relay coil should read between 40 and 80 ohm. If there is high resistance, the coil is failing although it may still be working, or it may not work when electrical loads are high. If there is no resistance on the coil, it has completely failed and the condenser fan relay needs to be replaced by a professional mechanic.
Over time, the condenser fan relay can also break. The easiest way to figure out if the relay in your vehicle is broken is to shake it. If there is a rattling sound inside, chances are the relay armature is broken and needs to be replaced.
If you do not feel any air circulating when you turn the air conditioner on, the condenser fan relay is likely bad. If you continue to use the air conditioning with a broken relay, the engine can overheat. This can require more extensive repairs than if you just had the condenser fan relay looked at.
Since the condenser fan relay can fail or break over time, you should be aware of the symptoms that indicate it needs to be replaced.
Signs your condenser fan relay needs to be replaced include:
- The engine is overheating
- The air conditioner is not working on a regular basis
- The air conditioner does not work at all
- No cool air is being blown out when you turn the air conditioning on
- You hear a rattling noise when you shake the condenser fan relay
Do not leave your condenser fan relay unattended as it can cause larger problems and it can be a health hazard in the warmer months. Consult a mechanic if you're experiencing any of the problems above. They will be able to diagnose your vehicle and make any repairs as necessary.
This article originally appeared on YourMechanic.com as How Long Does a Condenser Fan Relay Last? and was authored by Valerie Johnston.