'Stop engine hot' warning when stuck in traffic.

Hi I'm new to the forum and would appreciate some advice please

My son has a 2005 Citroen c3 1.4 sx which is running hot and he's getting the "Stop engine hot" warning when stuck in traffic. I had a look for him and the fan is not kicking in when it should.

where would you start with diagnosing the problem? Is it likely to be the fan itself, relay/fuse or a sensor? I believe the fuse can be a pain to get to and if it blown would there be an underlying reason? Any ideas how much the parts might be?

He has just had another big bill with a new throttle housing so we'd like to fix this ourselves if we can.

Any suggestions appreciated

Many thanks

Welcome to the forum prancinghorse68

There are 2 different wiring circuits for the Citroen C3 on a 2005 Petrol; those with air con/climate control and those without.

But, they both are fused by a 20A fuse (F8) in the engine bay fuse box. The fuse is not exclusive to the fan though, and its unlikely this is the problem, as other systems will also be affected. You can find the 2005 Citroen C3 engine bay fuse box layout in this forum post: citroen-c3-tips/c3-2002-to-2006-engine- ... -t157.html

To diagnose the fault, I would check for 12v at the fan when the fan is supposed to be running. If you get the 12v then the fan is faulty.

If you don't get 12v at the fan when its should be running, then its the fan control side that need looking at.

Depending on if the car has 'air con' or no 'air con', then I would proceed slightly differently as the 'air con' version has more computer control over the fan than the non 'air con' which has a relay to switch the fan.

If you are going to be working on the car, I do recommend the Haynes Manual for the C3 on eBay. Both the Blue and Green Haynes manuals cover the model and year you are having problems with.


There are some Citroen C3 1.4 i Petrol Radiator Cooling Fan Unit for about £85 on eBay, and Euro Car Parts (here) have them with free delivery. Enter the registration number to find the correct fan for your model on the euro car parts site.

Thanks for the advice very much appreciated.

Tried to test for 12 volts at the fan by unplugging the power lead and putting my multimeter across it but i think my multimeter is playing up as i got no reading. Then tested it on a battery i knew was working and still no reading!
Spoke to citroen and they said very unlikely to be a fuse as cooling fan (and other circuits) controlled by maxi fuse so other problems would be materialising.
It is the version with climate control so Citroen confirmed my suspicion that when air con switched on the cooling fan should also some on and it doesnt - totally dead.
I'm leaning toward it being the fan but will try another multimeter - i assume I'm doing that right by unplugging the power lead to the fan and putting the multimeter across the 2 terminals. (i did get a tiny spark but the cables got warm which was a worry!!).

Thanks again for the advice and links.

It is the version with climate control so Citroen confirmed my suspicion that when air con switched on the cooling fan should also some on and it doesnt - totally dead.

Its a little more complicated than that, the fan will come on when the computer thinks it should (and takes the air con status into consideration, and many other inputs too).

I'm leaning toward it being the fan but will try another multimeter

You need a working meter or test lamp otherwise any information you get from it will be meaningless.

I would have poked the meter leads into the back of the plug then tried to get the thing up to temperature and beyond (enough to bring the fan in). If that was too much bother or looked like it wasn't going to work, I would have used a 12v lamp across the fan terminals and then run a cable into the car and gone for a drive. You can see the light come on from within the car.

BUT its the air con (climate control) version so, even with 12v across 2 pin black plug you still need the computer signals on the 3 pin grey plug to get the fan running, at least its a start and may be all you need.

i did get a tiny spark but the cables got warm which was a worry!!

The meter leads should never get warm, the meter is faulty or on the wrong setting (ohms rather than VDC).

I am amazed how cheap the DMMs have become:

Ok so ive had the same issues as most people with the temp. a few tips before buying or going garages. first start the car from cold and then unplug the temp sensor if the guage goes up its not the sensor( please note there is only 1 sensor and this also used by the ecu) ilthere is a fan relay located next to the n/s headlight to check. my personal problem was thermostat was not working as it should. but good luck finding the problem cause it took me 4 months