Where is fan controller (Bitron Unit?) on 306?

Steve B · Post by **Steve B** » 04 Feb 2004, 00:11

Hi folks,
I recently posted a question about by 306 Meridian overheating in traffic. (Fans do not come on when they should)
I've found and checked the three fan control relays.
Now I think I need to find the fan controller (these used to be made by Bitron)
Can anyone advise where these live on a recent model 306 with air con ?
Many thanks,
- Steve

wheeler · Post by **wheeler** » 04 Feb 2004, 04:03

im not sure of the location on a 306 but depending on how late the model is the cooling fans may be controlled by the injection ECU,do you have three temp sensors (blue,brown & green) ? if it has 3 it will be bitron controlled.

Steve B · Post by **Steve B** » 06 Feb 2004, 00:07

Thanks, Wheeler.
That's really helpful.
It is a very late model 306, so perhaps the fans are controlled by the main ECU.. Not really what I wanted to hear though, sounds incredibly expensive [V]
I will take a look tomorrow to see if I can find sensors. Can you suggest where they might be? Near the thermostat housing perhaps?
Cheers,
- Steve

wheeler · Post by **wheeler** » 07 Feb 2004, 00:51

it should be near the thermostat housing,is it a petrol or diesel ? whats the engine size & year of the car ? if its that late a model is it not still under warranty ?

Steve B · Post by **Steve B** » 07 Feb 2004, 02:17

Hiya,
It's a 2000 year 306 Meridian 1.6 Petrol - So it's annoyingly a few months out of warranty!
I have read reports that the fan control unit on a 306 is usually in a recess under the nearside headlight, near the horn. I took the cover off that today.. and found nothing interesting [V]
I have, however, managed to find a circuit diagram whihc makes clear how it all works (assuming that mine does uses this technique). The voltages on the fan control relays tie up with the circuit, anyway...
Regarding the actual sensors, all I could find near the thermostat housing was a sensor with 3 wires - Not quite what I expected.
Still puzzled...
- Steve

wheeler · Post by **wheeler** » 07 Feb 2004, 05:07

is it possible to post the diagram on here ?,you may not have the correct diagram as there are so many variations,model year,with/without air con,multiplex,bosch,sagem or MM injection system.you have to use the diagam & check that all the connector colours & pin numbers corespond with whats on the car.being a 2000 model there is a very good chance it is ECU controlled & no bitron,i think this 3 pin sensor is a triple function,gauge,fans & cold start.

Steve B · Post by **Steve B** » 08 Feb 2004, 22:13

Yep, there seem to be many variations!
I'm hoping to get more information from someone who has access to the full wiring diagrams soon, so I'll take it from there!
-Steve

JR · Post by JR » 10 Feb 2004, 01:42

Hi Steve,
Just came across these useful wiring diagrams on the web...
http://silverstone.fortunecity.com/impa ... ot_eng.htm
cheers, JR

Steve B · Post by **Steve B** » 11 Feb 2004, 06:11

Thanks, JR - Much appreciated.
I actually just stumbled across those circuits myself...
Unfortunately, it looks like the one I really need is not there.
It appears that some very late model 306s use the main engine ECU to control the fans as opposed to a separate box.
Hope mine is not broken, sounds awfully expensive..
Cheers !
- Steve

JR · Post by JR » 12 Feb 2004, 01:42

Hi Steve
The sure way to establish if the ECU is faulty, is to take your car to a Peugeot dealership. They will be able to hook your car up to a Peugeot diagnostic tester for a reading. A test itself should not be expensive, but as you have guessed, a replacement ECU is not cheap. It's possible, you may just have a faulty sesnor, which the diagnostic test will also determine.
Just one other thought - have you tried resetting the ECU? You can do this by disconnecting the battery for around half an hour.
Cheers, JR