rapide engine fan issue

[lights2flag]

Hi all
new to the forums here.
I have a Rapide from 2014 that has some electronic gremlins I would like some help/input on. US car (located in EU) with 25000 miles on the clock.

The engine fans are on (at high speed) all the time. Just with battery connected even. Car starts and runs fine. No warning lamps and no fault codes related to cooling system...
The temperature gauge works as it should...does not over heat at all. So I believe the temp sender up by thermostat housing is ok and working as should.
Is there another sensor I should look for? Is there a relay pack of sorts that can be bad?
I should add that I believe this car was hit at some point in right front area...but from what I was told it was just body damage (bumper, wing and lamp)
Does anyone on here have a wiring diagram I can have a look at?
Anyone experienced similar issues?
any help would be greatly appreciated
Thanks in advance
Don

[EVR]

I had a similar problem on my Maserati GranTurismo, one day the fans stayed always on even with the car off & locked. Needless to say, this drained the battery in no time.

The fault was a very simple relay that broke and never opened the fan circuit. A 4€ reparation, so my suggestion is to start and look into these.

[paulrog1]

There is a relay in the engine bay fusebox, that's a cheap part to replace, try that first.

Other than that the temp sensor that goes into the engine thermostat housing, you can get an electrical Multimeter set on resistance and see resistance change when the car is warming up, the resistance from memory goes down as the engine warms up, should around 2500 ohms when the engine is cold and that resistance drops significantly when the engine warms up.

The fan is controlled by the car PCM and uses pulse width modulation (PWM) to control the speed of both fans.

There is a controller in the fan pack, these seem to be reliable but maybe faulty due to a collision.

Edited by paulrog1 on Tuesday 25th November 17:14

Edited by paulrog1 on Tuesday 25th November 17:16

[p102768]

Does the ambient temperature display correctly because that sensor can cause weird issues when it goes bad?

[lights2flag]

Thanks for the quick responses!
I can't seem to locate a relay diagram to show which relay is which in the engine comp box. I do have access to a wiring diagram from a db9 which I believe is almost identical. And that shows only the fan modules having battery power all the time and a trigger wire that comes from the engine ecu (brown/yellow)
When I have time later I will disconnect that cable to see if the problem goes away and that will eliminate or locate a fault within the ecu
The temp sender is working as it should and also the ambient temperature sensor...

[guards red]

I would suspect that the fan relay has jammed in the on position.

Locate that and give it a sharp tap with the handle of a screwdriver. If the fans stop you need a new relay.

[camel_landy]

Another thing worth considering is if it's related to the AC, rather than engine temp.

Just a thought.

M

[lights2flag]

Problem solved!
after a few hours of messing around checking relays and sensors I decided to check the signal wire from eco to the fan modules..remove rf inner wheel arch and its up in there. I load tested it (brown and yellow cable) and found it to be broken. then I looked under the lh inner wheel arch and found a connector just like the ones on the modules which was broken and the brown/yellow cable was backed out of its holder. I didn't think of this earlier because when I volt tested that cable at the fan modules there was around 3v but that must be back voltage from the 12v input.
basically its solved. thanks to all for the inputs
don