Symptoms of a Faulty or Faulty Thermal Coolant Fan Switch
Common symptoms include an engine overheating, a Check Engine light coming on, and a broken or shorter signal wire.
The coolant fan switch is a small and very simple switch, usually consisting of two wires. This switch is set to operate based on engine temperature. When the engine temperature rises to a certain threshold, the switch is activated, turning on the coolant fan. The coolant fan will continue to operate until the engine temperature drops to a predetermined level. Once the temperature reaches this cooling stage, the coolant fan will turn off. Although the coolant fan switch is very small and sometimes overlooked, it is an incredibly important component of your vehicle's cooling system. Think of this switch as a "gatekeeper" for controlling the temperature in your car's engine. There are many other engine systems that are also indirectly affected by the operation of this switch, but in the context of this article, we will focus on its relationship to the operation of the coolant fan. Several symptoms can point to a bad or faulty thermal coolant fan switch.
1. Engine overheating
Motors generate enormous amounts of heat and, as a result, are subject to very large temperature fluctuations if this switch is not operating efficiently. When this happens, the result can be extremely devastating, resulting in thousands of dollars worth of engine damage. A common symptom of a bad switch, which can also be alarming, is that the switch will simply not turn on the fans at the set temperature level, causing the motor to heat up beyond what it needs to be to run efficiently. When the temperature exceeds this threshold, many other components begin to fail, in addition to reducing engine performance.
2. Check Engine light comes on.
Luckily, when this happens, your Check Engine light will be on and, depending on the car model, an additional “hot engine” symbol will also appear on the dashboard. This is a very critical time to get the car home or to a place where it won't be driven until it's been inspected. In other cases, the switch will turn on and stay on well above the cooling temperature threshold, causing the fan to run even when the engine is off.
3. Broken or shortened signal wire
As mentioned earlier, there are two wires inside the switch. When one of these is broken, it can cause it to be intermittently grounded, causing the fan to run intermittently. A short circuit in either of the two wires can also result in intermittent operation, which again results in intermittent responses to the fan being turned on or off unexpectedly.
Because it is an electrical component, in the event of a malfunction, it is often difficult to predict when it is working and when it is not. As mentioned above, the coolant fan thermal switch is a very important item for the life of your engine, and replacing it is a very inexpensive part. Therefore, we recommend inviting an experienced AvtoTachki mechanic to your home or office to diagnose the problem.
