You have to plug in a tester and erase the overheat fault code from the ECU memory
It's the big fan that cools the rad.I presumed that the OP speaks about the electric cooling/aircon fan which has a retrofitted controll switch cos it's quite common...if my presumption was wrong so is my answer
It's the big fan that cools the rad.
Do u have air-con? if so the electric fan in front of the radiator is part of that system.
Do u have a fan at the rear of the radiator? if so that is a viscous coupled fan for cooling the radiator.
that fan does turn all the time, it has no electrical control or power, it is driven direct from the engine through a viscous coupling which means hough it turns all the time theres no real power or air passing through it till air passing through rad heats it ,once the coupling is locked the fan been driven fully is noticeable by the sound it makes,coupling can seize which you can test by trying to stop fan with a rolled up newspaper, a good one will stopYes it's the fan behind the rad (engine side of rad). It now runs all the time since it overheated. It sounds like sierrafery is right and it will need plugging in to reset it.
Forget what i said, i presumed that it's the other (electric/aircon) fan as you spoke about a switch and "being on all the time" which for me meant that without engine running only with ignition on.Yes it's the fan behind the rad (engine side of rad). It now runs all the time since it overheated. It sounds like sierrafery is right and it will need plugging in to reset it.
that fan does turn all the time, it has no electrical control or power, it is driven direct from the engine through a viscous coupling which means hough it turns all the time theres no real power or air passing through it till air passing through rad heats it ,once the coupling is locked the fan been driven fully is noticeable by the sound it makes,coupling can seize which you can test by trying to stop fan with a rolled up newspaper, a good one will stop
Sorry sierrafery, that's my lack of knowledgeForget what i said, i presumed that it's the other (electric/aircon) fan as you spoke about a switch and "being on all the time" which for me meant that without engine running only with ignition on.
You should hear the fan when u first start-up with a cold engine the fan is then stiff to turn (locked) it may sound like a turbo fan for just 30-60 seconds or the first 50yards or so, then it goes quiet as the viscous fluid transfers within the coupling, only to lock up again in say heavy traffic on a hot day as mine does, but then as u have a diesel u may not hear it so easy. .
maybe on some other modells but on a D2 is used by the engine management for additional cooling if the coolant temp exceeds 110*C regardless of the aircon, and that's the case when it will run all the time on overheat fault code which must be erased to stop it(what i thought in my first answer as the OP spoke about a switch which is not the case for the viscous fan)air con fan only comes into play when air con is working, however it can be "tweaked" to come on without, if necessary
ah - OK. I was thinking of the D1.maybe on some other modells but on a D2 is used by the engine management for additional cooling if the coolant temp exceeds 110*C regardless of the aircon, and that's the case when it will run all the time on overheat fault code which must be erased to stop it(what i thought in my first answer as the OP spoke about a switch which is not the case for the viscous fan)