What is a AUX fan relay?
The aux fan is run from two circuits, one is the sensor in the radiator (which sends a signal to the relay you already tested) and the other off the AC/defrost circuit. The fan will only run when the sensor gets to a certain temp, or whenever the AC/defrost is turned on (the other circuit).
How do you test an auxiliary fan?
You will need to look at the ETM for the correct pin out or color wire. Then insert the other in the low (91) hole, the fan should turn on at low speed, then try the high (99) hole, should go on at high. If the high works and the low does not, it can be your relay or the aux fan resistor.
How do you test a fan temperature switch?
Turn on the burner and slowly increase the water temperature. The ohmeter should be turned on and have a reading of high resistance. When the water reaches between 180 to 220 degrees Fahrenheit, the switch should turn on and the resistance seen by the ohmmeter should change to zero.
How can you tell if a fan relay is bad?
Bad Cooling Fan Relay Symptoms
- The engine runs hot or overheats.
- The cooling fans don’t work.
- The cooling fans keep running.
- Warning lights.
- Poor air conditioning performance.
- Swapping Relays.
- Measuring the Relay Coil’s Resistance.
- Listening for Noises.
How do I know if my radiator fan is working?
Check the engine coolant level. If your engine coolant’s too low, it means that the cooling fan will have to work harder to keep the engine at a normal temperature. To check the level, look for the coolant expansion tank in the engine bay. There are usually two marks on it – a minimum and maximum level mark.
How do you test a radiator cooling fan motor?
How to Check a Radiator Fan
- Determine whether your radiator fan is manual or electric.
- To check an electric radiator fan, start the car and let it get up to the temperature where the fan normally kicks on.
- Use the volt meter to test if there is power to the wires.
- Normal voltage for a radiator fan is around 12 volts.
How do I know if my fan relay is bad?