WTD: Fan Relay Box for Peugeot 306

[matara]

My fan's aren't kicking in at 92 or 97 degrees and in stop start traffic the temp gauge is climbing between 95 and 100. If I turn the a/c on it runs the fans on half speed and that brings it back down to 70/80 degrees.

I have tested the fan circuit and relays and verified they are all working ok, even replace the temp sensor. Only thing left is the Bitron relay unit under the front guard. Does anyone have a spare one of these they can send to me in Sydney. Car is a 2001 Rallye 2.0.

Thanks

Steve

 

[AlexB]

My fan's aren't kicking in at 92 or 97 degrees and in stop start traffic the temp gauge is climbing between 95 and 100. If I turn the a/c on it runs the fans on half speed and that brings it back down to 70/80 degrees.
I have tested the fan circuit and relays and verified they are all working ok, even replace the temp sensor. Only thing left is the Bitron relay unit under the front guard. Does anyone have a spare one of these they can send to me in Sydney. Car is a 2001 Rallye 2.0.
Thanks
Steve

Your description pretty much confirms the Bitron is working correctly as it matches the behaviour of my 306 in traffic when a/c isn't working.
My assumption is that with a/c on and the fans running at half speed is enough to stop thermal runaway. With a/c off the half speed is enabled at 96 degC but at that temp half speed is not enough to bring it back down and it over shoots to 100 ish DegC when high speed is enabled which then brings it down until your next traffic light stop. I would start to get concerned if it stayed above 100 and you notice the a/c is no longer blowing cold air because the bitron has disabled the compressor clutch.
The Carter in your pic and the grey faced Bitron have the same setpoints, there is a green faced Bitron (I think was used in a Citroen VTS) that enables the low speed fans at 92 degC and has a 10 minute cool down.

The brown temp sensor is a PTC so any minor increase in resistance raises the temp the fans will cut-in, so it's worth cleaning the brown sensor plug and the 15pin connector to the Bitron, I posted some resistance measurements in another post and if they don't match then it's worth also checking for moisture and cleaning the 2 large (engine harness to the front harness) round plugs on the chassis rail below the bitron.

306 has three temp sensors, only the VE=Green sensor used by the engine computer can be seen via OBD/PP2000.
BE= Blue sensor is for the temp gauge AND earths the STOP dash tell tale.
MR=Brown/Maroon is used by the Bitron fan controller.
The bitron can also earth the STOP dash tell tale.

After reseating the connectors you check the bitron and fans operate correctly by turning ignition on and unplugging the brown sensor. After a few seconds you'll hear the low speed fan and then both fans full speed. Reconnect the brown sensor and the fans will turn off confirming the fans and Bitron unit are functional.

306 Cooling fan and STOP light

Hi guys, Having an issue where the cooling fans run on low speed for about 5 minutes after turning the engine off. The dash STOP light is also coming on after driving for some time. If I stop and let the car cool down, the STOP light goes off. When I did this I opened the radiator cap, coolant...

www.aussiefrogs.com

 

[AlexB]

It's also worthwhile bleeding the coolant system, I've often wondered if an air pocket gets stuck in the thermostat housing at idle which would play havoc with reliable temp readings.