Does a car fan need a relay?
The relay directs the cooling fan that is in the engine. It also controls the fan for the A/C condenser and conserves electricity. An engine can be severely damaged by overheating. The fan is critical to the health of your engine and if something goes wrong with it, it must be replaced immediately.
How do you check for a faulty relay?
The only tool required to check a relay is a multimeter. With the relay removed from the fuse box, the multimeter set to measure DC voltage and the switch in the cab activated, first check to see if there are 12 volts at the 85 position in the fuse box where the relay plugs in (or wherever the relay is located).
Where is the relay on a radiator fan?
The fan relay is often located in the engine bay’s fuse box, but the best way is to check your repair manual to find where it is located. Testing a 4 pin relay is often very straightforward. Remove the relay and give 12 volts to pin 30 and 85. Ground pin 86 and check if there is voltage coming out from pin 87.
How can you tell if a relay has a blown fuse?
If voltage is able to flow through that side of the relay, move on to the 87 connection point and determine if battery voltage is present there. If it isn’t, that also suggests a blown fuse or circuit breaker. Checking the connection points in the fuse box with a multimeter will confirm if battery voltage is available at the relay terminals.
Where is the fuse on a car cooling fan?
Your car’s manual should show where the fuse for the cooling system is. If the fuse has gone, the mechanic will need to replace it right away. On most modern cars, the cooling fan is controlled by the Engine Control Unit (ECU) which gets a signal from the coolant temperature sensor.
How can I tell if my cooling fan relay is bad?
There are several ways to tell if a bad cooling fan relay is to blame for an overheated engine. The easiest method is to start the engine and then turn on the air conditioning. If the fan doesn’t engage, there may be something wrong with the cooling fan relay.
The only tool required to check a relay is a multimeter. With the relay removed from the fuse box, the multimeter set to measure DC voltage and the switch in the cab activated, first check to see if there are 12 volts at the 85 position in the fuse box where the relay plugs in (or wherever the relay is located).
The fan relay is often located in the engine bay’s fuse box, but the best way is to check your repair manual to find where it is located. Testing a 4 pin relay is often very straightforward. Remove the relay and give 12 volts to pin 30 and 85. Ground pin 86 and check if there is voltage coming out from pin 87.
If voltage is able to flow through that side of the relay, move on to the 87 connection point and determine if battery voltage is present there. If it isn’t, that also suggests a blown fuse or circuit breaker. Checking the connection points in the fuse box with a multimeter will confirm if battery voltage is available at the relay terminals.