Am i checking the cooling fan correctly

den9112 · Post Mon Feb 24, 2014 9:35 am

Hi,the fan on my citreeon c3 2003 is stil not working,i had the problem a month ago when i purchased the car,the dealer put a fan in from a donor car (a 2002 model) and it worked,however warranty is now out and the fan is not working again,now i have put a Multimetre on the large two wire plug with ignition off and it is showing 12v so am i correct in saying power is getting to the fan ,the temp gauge shows the bars going when when the car as reached temp and also goes down when traveling on a long stretch when it hits three so i would presume the temp gauge is working ,new fans are not cheap so any help in trying to eliminate what the issue coud be before i have to buy a new fan would be apreciated,also it as AC and that used to work but now when i switch on the fan does not move.Thanks

C3CAR · Post Mon Feb 24, 2014 12:01 pm

Hi Den9112

There are several different fans fitted to the C3s, some quite simple and controlled by a relay and others, with multiple speeds are solid state controlled.

Fan relay, C3 - quite well hidden.

I think you can tell by the number of wires to the fan. If you only have 2, then check for 12v to earth or battery negative then check the fan negative to earth for continuity.

If you have more than 2 wires;

C3driver52 wrote: did a few tests on the control signal for the fan unit on a Diesel C3. lexia gave me the option to test the fan which powers up the fan then changes the control signal to slow the fan speed down until it stops. lexia then reports that the fan worked as expected.

During the test I managed to stick some meter probes into the control wires on the plug on the fan. The wire colours are going to be different to the petrol version, but hopefully the control system will be similar.

The diesel has a 3 pin plug. One wire (white) always read 12v to battery earth (its fed from the BSI), Yellow didn't read anything (fed from the Engine ECU) and the pinky purple one (fed from the Engine ECU) measured 8v (to battery earth) which decreased as the fan slowed down. Its highly possible the pinky purple was more than 8v before I managed to look at the meter, so Its probably 12V for full fan speed.

My guess is the yellow is the 'low fan speed' option that the diagnostics offered, but didn't seem to respond, so I guess its not fitted to that particular model.

den9112 wrote:the temp gauge shows the bars going when when the car as reached temp and also goes down when traveling on a long stretch when it hits three so i would presume the temp gauge is working

The temperature gauge should go to 3 bars when warm and stay at 3 bars for the entire journey. You may have a bad thermostat if the bars keep dropping, or fan if the bars keep rising.

: Citroen C3 thermometer showing 3 bars

Engine cooling at 3 bars

den9112 · Post Mon Feb 24, 2014 2:01 pm

Update on the fan problem,the car was taken to a local garage,they tested the fan by bridging the temp sensor(top green one) and the fan came on ,new one ordered and when fitted the temp bars went high and fan came on ,just waiting to call back to see if all is ok, also the car as never run with three bars ,when it goes to 3 bars it goes back to two on a long run......Just got back from garage,i am told that the diag machine is saying open circuit,he says he can clear it but as soon as ignition goes on it comes back,it apears that this is the issue with the fan not coming on ,he says he wil put it on live data tommorrow...i am wondering if this as anything to do with the AC as it was working when i got the car buti now cant hear the compressor kicking in.

C3CAR · Post Mon Feb 24, 2014 4:13 pm

i am wondering if this as anything to do with the AC as it was working when i got the car buti now cant hear the compressor kicking in.

Thanks for the update.

The engine ECU has a hand in the air con control. I would expect air con to be disabled if the ECU detects a problem with engine cooling.

den9112 · Post Mon Feb 24, 2014 7:07 pm

Thanks for the reply, could you please tell me if the worst case scenario would be a repaired BSI , also when the car gets to three bars (heavy traffic) it goes back down to two after a couple of miles at 30mph ,the car as yet to overheat but with spring and warmer temps round the corner I need to get this sorted.

C3CAR · Post Mon Feb 24, 2014 7:53 pm

could you please tell me if the worst case scenario would be a repaired BSI

Engine ECU is the one that would be my best guess at a worst case scenario

also when the car gets to three bars (heavy traffic) it goes back down to two after a couple of miles at 30mph ,the car as yet to overheat

Sounds like the thermostat is stuck open.

Citroen C3 Thermostat housings available on eBay

den9112 · Post Mon Feb 24, 2014 9:13 pm

Replies are appreciated , could the thermostat sticking open cause any issues with the coolant temp not talking to to BSI thus not kicking the fan in,long shot I know ,I have checked a couple of BSI repairers ,one is rollington motors and the other is bba reman,both with a 5/7 day turnaround ,one thing I did do today was the BBA reman BSI reset,it didn't sort my fan out but it got my clock display working again after fitting a aftermarket HD

den9112 · Post Tue Feb 25, 2014 11:16 am

Quick update,this problem is now causing me a great problem, the garage don't seem to be able to sort it,i am having to leave the car sort out arrangements for work ,then pick it up still not fixed,normaly I wouldn't worry but I know this is going to cause me big problems when the weather is warmer,i did ask if their was a way of doing away with the computer side of the fan ,he tells me you can get a kit were you do away with the computer side ....the car works perfect apart from this annoying fan just not cutting in,if any one knows of these fan kits it would help as I would rather do that than just chasing the problem in the garage were its costing me money without results .

Arfur Dent · Post Tue Feb 25, 2014 2:08 pm

den9112 wrote:if any one knows of these fan kits

Yes, I have used one myself on a non computer controlled car.

Just like one of these kits (click here) on ebay. They were a popular upgrade to kit cars. Easy to fit, but you may need to be clever with the fan fitting.

But if your fan is working OK, then you just need the kenlowe fan control kit (here) and use it to control your existing fan.

: kenlowe fan control kit

This is the control part - of the kenlowe fan kit.

C3CAR · Post Tue Feb 25, 2014 2:20 pm

den9112 wrote:could the thermostat sticking open cause any issues with the coolant temp not talking to to BSI thus not kicking the fan in,

The thermostat stuck open can stop the car getting to temperature and therefore the computer won't engage the fan.

den9112 wrote:I have checked a couple of BSI repairers ,one is rollington motors and the other is bba reman,both with a 5/7 day turnaround ,one thing I did do today was the BBA reman BSI reset,

I don't think you have a BSI problem. It all seems to be engine related, so its the engine ECU you would be looking at. But thermostat is much cheaper to replace along with the temperature sensors (some have 2 some have only 1), also check the engine ecu wiring to the temperature sensors.

: C3 Engine ECU location

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