warning message on lights and trailer lights but no trailer attached!!!

[martinpage23]

Hi, today while i was driving home a got a warning message come up saying CHECK TRAILER LIGHTS, problem is i am not pulling a trailer. when the message is showing the indicators will flash fast when on. then when i brake it tends to go off and all is fine. then while driving it will come back and the go and come back etc. found out that when the error is showing my fog and reverse lights don't work. but all other lights are fine. i parked up and found when the error is not showing everything is fine but then while standing out side the car the fog and reverse light would suddenly go out and the euro would be showing then the message may go after 2 to 10 minutes and fog and reverse lights would come on. did think it could be a loose connection but was doing it while the car was still....... not sure what to check on this .  please help. its on a 05 reg x5 sport. 

[X5Sport]

Water in the plug on the tow bar would be my guess.  It's likely to be a short on one of the pins meaning the car thinks there's a trailer attached and changes the lighting checks to include the trailer.

[martinpage23]

Ah that would be a good place to check. So it could just sort it's self out when it gets dry??? If it is that

[X5Sport]

It might.  Once it does then check the plug/socket as it should keep water out.

[chrisn7]

It would be best to get the plug dried out, as the water can track back along the wiring by way by capillary action to, say, the trailer module and do for that as well.

For example, this very problem is well known in the E38 where coolant tracks all the way from the electronic thermostat to the DME of all things -  a distance of perhaps 4 feet-much further than the X5 trailer module to trailer socket harness.

All the plug wiring will turn green too and this corrosion will lead to intermittent or non functioning trailer lights