Engine cooling fan and wet road.

[humbersin]

Hi all, I have noticed that the electro fan of the engine starts blowing at basically any temperature after been driving on wet conditions sometimes bellow or around 80 deg. Then, after re-start the engine and with the temp bellow 50 deg comes again and it doesn't stop at all. I have checked the electronic switch inside the inner N/S wing (I also managed to open it) and seems to be as dry as a bone with no visible indications of damage at all. The air con has not been switched on. Not even the fan of the cabin
just to make sure not interfere with the testing I was doing.
I have also checked for signs of damp in the fuses box and the relays box and they are also dry.

I can only think that there is another sensor somewhere sending the wrong information after getting wet creating an earth connection, a short circuit or something like that but honestly I have no idea where it might be.

As I am running out of things to check can anyone give me a clue where to look at? Please do not suggest the "stealers". The car is a 1999 c180 W202 auto with only one electric fan. All ideas or suggestions will be more than welcomed.

 

[television]

Do check that there is no water in the fuse boxes with 2 lids as water can get under the SAM if there is there are modified lids now

 

[humbersin]

Thanks for your suggestion Malcom but no water under the boxes. It used to be a blind grummet and I removed it some time ago because looking for this it used to be some water stored under the fuses box (the closer one to the windscreen to be more precise) so the water now runs down through the wing. The problem start when the car is drven on a wet road not when is raining and the car is stationary since before the rain. That suggested to me that it happen only with the spray of the road under the car.

 

[television]

The only 2 things that I have are the box under the wheel arch and the water under the SAM,, I will look to see if there is an update on this

 

[humbersin]

Please because I am getting paranoid with this

 

[television]

I can send you 3 papers on this subject, thats all I have

Please PM your Email address

The sensor on the top of head could do ti but not when damp I think

 

[Aviator]

When the fan runs unplug the sensor and see if it stops.

 

[television]

3 Emails sent

 

[humbersin]

Aviator, thanks for your suggestion but the only sensor I have ( I think ) is the one situated under the front black plastic cover at the front of the engine, and that is for the gauge on the cluster. Of course I have unplugged it and the only thing it does is bringing to zero the gauge.

 

[humbersin]

Malcom, thanx for the papers. I didn't write to you before because I had some problems with my computer, sorry about that.
The papers make reference to older years than my car. My car was built in Bremen as indicated by the VID but by 1999 the mods for the fuses box was already introduced as a normal part to put in the assembly chain.
Other think I didn't comment to you is that when I unplug the MAF the fan start blowing in full blast (if it is in a dry weather conditions and it was off) and stops again as soon i plug it back. Is it normal that the MAF can trigger the fan????

 

[television]

Malcom, thanx for the papers. I didn't write to you before because I had some problems with my computer, sorry about that.
The papers make reference to older years than my car. My car was built in Bremen as indicated by the VID but by 1999 the mods for the fuses box was already introduced as a normal part to put in the assembly chain.
Other think I didn't comment to you is that when I unplug the MAF the fan start blowing in full blast (if it is in a dry weather conditions and it was off) and stops again as soon i plug it back. Is it normal that the MAF can trigger the fan????

The stupid faults point towards a SAM being corrupt through damp, now the fan has no connection with the fan,,only when the signals get muddled up via a SAM

 

[television]

Looking at the state of the SAM on my car, it looks perfect from the outside when I took it off there was corrosion all over the pins making the car do silly things, It must be this SAM

 

[humbersin]

Malcom, again thanks!.
I had a go today with the SAM as you appointed. It was a sign of a verdigris in some of the pins (in the first one basically) which I cleaned the best way I could with a brush, very fine wet and dry sand paper and WD40.
Apparently there is no further damage inside although I didn't even attempted to open it. I also, after all the cleaning put a "jacket" made with a plastic bag before screwing back the cover. Also I covered the same way the fuses box.
The result of this entire works made the magic. With the air con on the fan started in first stage and stopped when the air con was switched off, and it didn't started at all when I re-started the engine (hot, around 80)as it used to happen before. So, for the time being, so far so good.
I will keep you updated regarding whether was successful what I did or not within the next few days.
Regards,

Humberto

 

[television]

Good luck young man