Strange thing happening....even when engine is cold one of the front fans on my "06C4S will come on.....car runs fine.....seems to cycle on and off at various times. Any ideas? relay problem?

 

The same fans are used for both engine cooling and A/C. The first thing to do is to turn off your A/C (A/C Off button) and see if the fan still runs. The A/C system can cause the fan to come on regardless of engine temperature.

 

Another thing you can check is if the fan that isn't running is jammed. Physically try spinning the non-running fan and see if you can free it up.

 

Good catch by devil boy, I missed the fact it was a single fan. The fact that it is on early is still probably due to activation by the A/C system, but the fact it is a single fan running hard denotes that either one fan is stuck, one fan has failed, or the controller has failed. There are other threads about this, search for them. The service advisor told me that the controller has a fail-safe built into it that turns the remaining fan on full blast if the other fan can no longer be turned on.

In the case of my 2006 it was due to a controller failure but it was replaced under CPO. Others in some of the other threads found debris in the fan to be the culprit. That seems to be the first thing to check if you aren't still under CPO.

 

Thanks for the input....took the car to my mech and of course could not duplicate the issue....turned fan on/off and drove it around....nothing but normal

 

Like mentioned above, check to see if fan is blocked by debris, you can reach it by removing the wheel liner.

 

Yes. All checked. No debris. No blockage

 

The only time this has happened to me was because the other sides electric fan failed.