What are the relays for the radiator fan?
The 5 fan relays change that into 3 wires going to the fan module: low, medium and high. (There’s another wire somewhere for the ground return.) In the fan, the low and medium run though resistors and a thermal fuse. High is direct and bypasses the thermal fuse.
What are the symptoms of a bad cooling fan relay?
1. Engine running hot One of the first symptoms commonly associated with a bad or failing cooling fan relay is an engine that runs hot or overheats. If you notice that your engine is running at higher temperatures than normal, that may be a sign that the relay is not functioning properly.
Are there low, medium, and high speed fan relays?
Coming out of the BCM, there are two lines. One for low speed, one for medium speed, and both for high. The 5 fan relays change that into 3 wires going to the fan module: low, medium and high. (There’s another wire somewhere for the ground return.) In the fan, the low and medium run though resistors and a thermal fuse.
When do you turn on the fan relay?
When the correct parameters are met, a temperature switch or the computer will activate the relay, which will allow power to the fans. The relay will usually be activated once it is detected that the vehicle’s temperature approaches excessively high temperatures.
When to turn on the cooling fan relay?
The cooling fan relay is an electromagnetic switch that controls the power supply to the engine’s cooling fans. It ensures that the energy-intensive devices only run when needed, usually when the vehicle is immobile. When the engine temperature approaches unsafe levels, the vehicle’s computer or temperature switch turns on the cooling fan relay.
What happens when a radiator relay goes bad?
A faulty or broken relay cannot deliver power to the cooling fans. In turn, the unpowered fans won’t run, leaving the radiator to its own devices. Deprived of the helpful influx of air from the cooling fans, the radiator cannot remove as much heat as it usually does.
Why are my cooling fans running at all times?
3. Cooling fans stay on at all times. If the cooling fans are staying on at all times, this is another (less common) symptom of a possible problem with the cooling fan relay. If the relay shorts internally, it may cause power to be permanently switched on, which will cause the fans to run at all times.
Can a bad fan relay cause an engine to overheat?
However, a bad cooling fan relay isn’t the only culprit for excessively high engine temperatures. Many other issues can cause the engine to run hot or overheat. Rather than uncommonly high engine temps, the driver may notice that the cooling fans have stopped running.