Peacheyd

So a few days ago , i got out of my car after a drive so short that the engine barely made it to operating temp. When i got out the car and locked it, the radiator fan came on for a minuite or so.
Since this day , now i have noticed the fan will come on and off all the time, even if the car is sitting with ignition on but engine off, it will still come on in short bursts.

First thing i have done is check coolant and oil, and all are fine,
The temperature gauge shows around 85 degrees C, which is normal so it cant be a thermostat , or an actual hot engine.

Where i live , at the moment the outside temperature will go form around 5 Degrees C to 15 throughout the day , so its cold out.

So my next thought was , the climate control. the Car will still cycle the fan on Full speed with climate on Hot,Cold or Off completely .

Which leaves (to the best of my very limited knowledge ) the fan Relay itself which , i think im right in saying is part of the whole fan assembly.
Ive seen a few threads on other Mercs where a lose connection has caused this but the engine was so different i couldn't really make out if the connections were the same on my car

So before i start looking at the replacement of the assembly, Can any of you guys suggest any other things to try through process of illimination ?

I did unplug both batteries and left for around 20mins to see if an old fault code was causing it and that it might clear it. and lastly , given the conditions of my local weather, do you guys think it will be
ok to unplug the fan assembly completely until i get this fixed? I cant see the engine over heating this time of year.

I did also think that weird fault like this can be caused by low battery voltage but everything else seems ok in the car.

the car is :

2007 W216 CL500 5.5L with 56K on the clock .

Thanks in advance
Dave

bbirdwell

Don't forget that a faulty coolant temperature sensor can also cause this issue.

Peacheyd

Wouldn't My temp gauge show something obscure , or nothing at all? it still sits at 85.