Hi folks,I've got a late model 306 with Air Con.The two cooling fans are not cutting in when the engine gets hot in traffic,although they do both run when the air con is switched on.I've found 3 relays near the radiator that appear to control the fans, andthey all test OK.Has anyone experience of the wiring of the fans, or what controls them ?Many thanks,- Steve

I have had similar problems with my fans on my 205 TD.It was the thermal switch mounted on the radiator that had failed. I havehad several over recent years, and after getting sick of keep swapping themI have replaced the Peugeot switch with two thermal switches I bought fromFarnell (see I mounted these at the top of my radiator, on a flange bit. It means a bitof wiring, but much more reliable.Nick94 205 TD

306 coolant fan control - advice please ?

Feb 03, 2004 25 Replies

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Nigel 22 years ago

The fan control is the ECU. It takes its information from the water temperature sensor. You have two, according to your photo. The one that sends to the ECU is the three wire one on top. The other one you can just about see is for the gauge. I suggest you try a new one of these (part number 1338A6). I also found out that the fans should come on slow when the aircon is switched on, but when the aircon is going flat out, then they should run on fast. (By the way, it was unclear on the parts page for your chassis number , how many fans you should have!! I think you said at the start of this you had two, yes?) You might want to check the earth point, which is just in front of the battery carries, on the chassis. Take the bolt out and clean everything. Make sure the bolt is tight afterwards. If all this doesn't work, then you will have to bite the bullet and get your dealer to put it on the Diag, to find out whether the ECU is receiving the information from the sensor, and if it is also earthing the relays to get the fans going. Good luck.

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Steve B 22 years ago

Nigel, Thanks, that is really invaluable information. I have access to an almost identical (but less faulty!) car tomorrow, so I'm going to try to persaude the owner to let me measure the sensor resistances on his! That should help. I'll let you know.... Cheers -

- Steve

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Steve B 22 years ago

Nigel,

So far I've been able to compare the resistances of the 3 wire sensor to a similar car, and they look very similar at approx 10C and 70C. I tried to test the other sensor (which has only one wire!) with a view to comparing it but couldn't work out quite how to get the connector off without breaking it.. Duh! Hopefully I will be able to do some more tests at the weekend.

- Steve

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Nigel 22 years ago

I think it's a "Bosch" type, held on with a wire clip on three sides. Push in the long side and the other two sides will unlock and you can pull the connector off.

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Steve B 22 years ago

Still there ? good... I've managed to unplug the second sensor, It has a purple ring on it and one wire going to it. It stays open circuit at 10C or 70C so I'm presuming that it's only a thermostatic switch to send to the STOP light ? Either that, or it's something else, and knackered

Next step ? Not sure, maybe get a dealer to interrogate the ECU to tell us what the ECU thinks the coolant temperature is ?

Cheers,

- Steve

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Nigel 22 years ago

I think you have probably gone as far as you can. You do need to get it on the Diag and see what the various readings are and whether there are any faults recorded. If and when you get this resolved, get an ECU download.

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