406 hdi cooling fan

[gez44]

Hi I have got a 1999 406 2.0l hdi 110.I was in traffic yesterday on the motorway which was stop start for over an hour .While i was in traffic a warning came on the mfd "engine temp too high".I stopped and looked around engine checking for leaks, etc non visible .I have never had this warning show before the car does not overheat or use any water.I have removed the grille and the relay cover with the three relays in it .I noticed some corrosion on the terminals on some of the relays so i replaced the corroded ones .I have also replaced the two fan resistors as these had gone open circuit .The only way i can get the fan to work is if i disconnect the temperature sender so does this mean the cooling fan electrical circuit is ok ?.I presume the fan started because the engine ecu could see no signal from the temperature sender and went into safe mode? The strange thing is that while in traffic the temperature gauge never went above 90 but the ecu must think it is hotter than that.Has any one got a wiring diagram i could look at or any knowledge of how the cooling fan electrics works?Sorry for the long post but better to get all the details out at once.Thank You

[Welly]

You say "the only way I can get the fan to work is disconnect the sensor" but if your a/c isn't working then you'd rarely see the engine cooling fan run unless things were really hot.

I had to replace my fan because it was drawing too much current.

Here's the fuse connected to the fan circuit (the one with paint on)...

[gez44]

Hi welly thanks for the reply.I have checked the fuse and wiring you have marked and they are all ok .I would have thought regardless if aircon is on or not if the engine got hot enough it would work like you say that aside the ecu must have thought it was too hot for the warning to appear on the mfd.I presume the ecu must get its information from the coolant sensor to show this warning . It would be handy to know what water temperature the warning comes on at because the engine must have been hotter than 90 which the gauge said it was.If it was then why did the fan not cut in?I was wondering if the coolant temp sender was sending wrong information back to the ecu thus not putting the fan on.Could any other member tell me what their car runs at to compare ?.Has anyone else ever had this warning appear on their car?Thank you

[DiscoPol]

Have read through this it should give some more info on the running temps

Polski