I have gone through 3 Fan Relay's in about 2 weeks with no Check Engine light or Error Codes. I have been searching for what could be causing this and finding nothing on it. SO I thought I would come into the Forums and try to find some help. Thanks in advance if anyone can help me out.

08 Accord 2.4 with 123k miles

 

What was the mode of failure in the relays?
Or how did they fail?

Did the coil burn out?
Did the switch stop moving?
Was it burnt contacts?

If you have been searching for a cause and found nothing??
What can we do??

 

welcome to the forum. relay failure could be the fan motor is taking excessive power to make it fail, but not shorted to burn the fuse. find out all the items on that relay that draws power and see if there may be anything to cause the failure of the relay.

 

Both fans still work as normal. Could it be going bad and taking more power than it should? Is there a inline fuse that I may be missing to casue the relay to blow?

 

A fuse is a current limiting device.
How would limiting current blow a relay?
If the fuse was changed to a higher current then maybe it might blow the relay

And as I said before, you have to know how the relay went bad before you can determine the cause

 

Im just trying to figure out why the relay would blow this quickly because something in the Cooling system is not working as should. Could Thermostat or Temperature Swith/Sensor cause this to amke the CPU believe the car is overheated??

 

If a temp sensor tells the ECU to turn on the fan
The ECU completes the circuit for the control side of the relay
This in turn (normally) pull a switch lever to close the load side circuit
This means it completes the circuit for the load side of the relay.

Relays are rated for voltage and current
Both of which help to determine the power rating of the relay.
The circuit should be designed to handle the expected currents and voltages
Failure modes could be burnt contacts, corroded pins, open circuit in either control or load side, short circuit, loose pin contacts

Measuring the resistance and visual inspection of the failed relay would help determine failure mode
If the fan or fans are taking more current than expected then the relay can over heat and eventually burn out (load side of relay)
If the relay fails on the control side then ECU may become suspect (doubtful)

Of course this does not preclude the relay could be of poor quality and/or design
Causing sparks and/or high transient currents which can cause premature failure of the relays.