TD4 radiator fans never come on ?

Had my 2004 TD4 just about a year now and have slowly fixed most probs.
New MAF with synergy 2, cleaned EGR, new BMW crancase vent.
The fans to the Radiators have never (ever) come on and a its hot in August here in Tenerife. Sometimes the engine 'crackles' when I shut her down after a lot of work in the mountains and it is obviously is hot, whereas the radiators are touchable and not working to their potential.
What sensors do I go looking to change, where are they and has anyone got the part numbers..... spent a few hours on the forum but cannot find anything.
Any mechanic fancy a Hol in Tenerife?

The TD4 is a super efficient diesel engine we use ours to tow trailers over mountains etc and the fans never ever come on unless we use aircon and then both fans fire up to cool the condensor. I shouldn't worry so long as the coolant level remains constant and the temperature gauge remains in the normal sector.

Hiya,

We had this problem 2 days ago when the fans failed on our 9 reg Freelander 2 going up Mount Ventoux in the S of france. As a result we boiled and were over taken by others in old clios and citrons laughing that their 10 year old french cars can go where a two year old freelander cannot. We suffered the humiliation of one french driver winding down his window and shouting out "**** english car" as he powered past in his ancient 405.

The AA came out and have not been able to fix it other than disconnecting and reconnecting the cables leading to the fans whilst the engine was running which seemed in essence to re-boot that part of the engine management system and the fans suddenly all kicked into life (radiator and air con)

I dont think this is a long term fix and we will be asking Stratstones to investigate this and the many other issues with the car when we return to the UK ....assuming it makes it !!!

put on your air con when engine is hot-the fan should then kick in

Hi All
Thanks guys for the input. I feel a little bit more at ease. My aircon has always been faulty and will get attention when the money is available. I was quoted €800 for a new compressor ! here in Tenerife. The red indicator light hardly shows when I turn on the aircon.
But, if the Radiators only come on when the aircon is On... that may be why.
Radiator liquid stays good at all times, so I will try disconnecting the rads when the engine is running and see if they kick in..... Will let you know