Heater has stopped blowing

I am quoting from a french site for the C3.

http://www.c3manuel.com/ventilation_chauffage-137.html

If you scroll down you will see that the wiring is different for the petrol and diesel.

With regards to removing the BSI once the clips are all unfastened is there any way to stop the earth plate sticking and lifting up from below? Any tricks at all? Just it seemed like it was going to break the last time i did it.

reddandanfireman wrote: ↑Fri Jan 08, 2021 10:02 am With regards to removing the BSI once the clips are all unfastened is there any way to stop the earth plate sticking and lifting up from below? Any tricks at all? Just it seemed like it was going to break the last time i did it.

Citroen C3 BSI removal topic

And the Citroen C3 BSM removal topic.

Ok clearly i didn't know what I was talking about i meant the BSM removal. Thanks for posting both of those threads, very helpful. Although I would like to add a the removal of the fuseboard is a bit tricky. Putting a flat blade either side of the fuseboard (bulkhead side and bumper side) then using a bigger one to prise from the driver side underneath whilst tapping the thread down as it starts to come up.

Refitted the new fuseboard (BSM) , then refitted the battery and commenced the BSI reset.

After doing this sadly the fan is still not working.

Just to recap, this all started after I hit a huge 6" deep pothole which ruined the top mount of the passenger front. It also damaged the front passenger headlight as it caught the bumper and pushed it upwards. I believe there is also a few maxi fuses hidden under the battery tray somewhere? Something to do with the diesel auxiliary heater element which requires high amperage fuses. I'm going to start looking there next if anything just to make sure there isn't a puddle of water in it.

Any further ideas would be very welcome guys thank so much for your help so far.

If you have a look at the circuit diagram (diesel) I will run you through the circuit.

Power comes from the positive terminal of the battery, BB00 through wire B03 to the terminal on the top of the BSM (labeled PSF1 in the circuit diagram).
Through fuse F18. So you should get battery volts on one side of the fuse contacts in the BSM if you pull the fuse out. Put the fuse back in. From the fuse to the internal relay contacts. Starting the car should energize the relay and close the relay contacts.
From the relay to pin 8 of the 16 pin green connector (labeled 16V VE on the diagram), should read about 14.5 volts on this pin with the engine running.
From the BSM to pin one of the fan connector (labeled 2V NR on device 8050). Should be about 14.5V here too.
Out pin 2 to to pin A4 of the control panel(labeled device 8025). Remove the connector from the back of the control panel. Measuring pin 2 of the fan or A4 of the control panel will give either 14.5v (fan OK) or NOT 14.5v (fan dead). In one of your last posts you said you were getting 8-9 volts here, that cant be right. There would have to be a very high resistance between this point and the BSM. If you are correct that indicates that there is a problem with the fan or the wiring between the BSM and the control panel (if you are measuring from pin A4).
Can you re-measure the voltage at A4 again and compare it to the voltage at the battery + terminal. If the voltage is not very close to the battery voltage then the most likely culprit is the fan.
Have you checked if the fan control resistor pack is getting hot? Labeled 8046.
For the next set of tests you will have to leave the 15 pin connector plugged into the control panel. You will need to try and poke the volt meter probes onto the connections where the wires come into the back of the connector. Turn the fan knob to a "medium" position.
Probe pins A1, A2, A3, A5. If they show 14.5V (or so) the the melted earth pin at B4 is not working.
You said you replaced the fan resistor so we'll assume that's OK.

Hi yes I'm assuming so far that the fan is the culprit. I was going to take the a4 pin and earth it off as suggested in other posts and see if that makes any movement from the fan. The resistor pack was replaced but after finding that didn't fix anything I took it back and put the original unit back in.

I can remove the stereo again fit a series of pins into the rear of the control panel multi plug and back probe them as suggested in another thread I hoping that the rest of the work on this car will be easy with regards to this problem now as the BSM was quite tricky. I tried it a year ago and decided cold feet was easier to deal with.

Again thanks for the prompt replies and help.

Ok here goes i've gone through everything i think. The first one came up bust after removing the f18 fuse i couldn't get a +ve reading from either side of the fuse connection, after putting a pin on point 8 of the green multiplug on the BSM though that returned 14.5v , on checking pin a4 again at the control panel it went from 9 to 14.5v so i must have had a bad earth where i was connecting the multi-meter.

Checking the resistor pack for heat i felt nothing. The following was a result for back probing the pins on the control panel, these were taken with the engine running and the fan on number 2 setting:

a1 = 0.19v
a2 = 0v
a3 = 0v
a5 = 0v

reddandanfireman wrote: ↑Fri Jan 08, 2021 3:54 pm

Just to recap, this all started after I hit a huge 6" deep pothole which ruined the top mount of the passenger front. It also damaged the front passenger headlight as it caught the bumper and pushed it upwards. I believe there is also a few maxi fuses hidden under the battery tray somewhere? Something to do with the diesel auxiliary heater element which requires high amperage fuses. I'm going to start looking there next if anything just to make sure there isn't a puddle of water in it.

Yes, the supplemental fuse box for the diesel engines is directly behind the near side headlight.

It has relays and fuses that are controlled by the engine ECU. As you say, often the extra heating element supply, but different models have different configurations in there.

Water is a problem for that supplemental fuse box in some situations where the bumper is not fitted.

Arfur Dent wrote: ↑Mon Jan 11, 2021 4:51 pm

reddandanfireman wrote: ↑Fri Jan 08, 2021 3:54 pm

Just to recap, this all started after I hit a huge 6" deep pothole which ruined the top mount of the passenger front. It also damaged the front passenger headlight as it caught the bumper and pushed it upwards. I believe there is also a few maxi fuses hidden under the battery tray somewhere? Something to do with the diesel auxiliary heater element which requires high amperage fuses. I'm going to start looking there next if anything just to make sure there isn't a puddle of water in it.

Yes, the supplemental fuse box for the diesel engines is directly behind the near side headlight.

It has relays and fuses that are controlled by the engine ECU. As you say, often the extra heating element supply, but different models have different configurations in there.

Water is a problem for that supplemental fuse box in some situations where the bumper is not fitted.



3897_glow-plug-relay-location-citroen-c3.jpg

Is that really where the glow plug relay is? Thats a terrible place to keep it. Trust the french honestly. They must have started with the glow plug relay and built the rest of the car around that jees. I'm at the point now where i can take most of the car apart. The glove box is out so i can remove the fan, the resistor pack is out and tomorrow i'll have the battery out to check under that. I'm beginning to think its likely the earth for the control panel is no longer connected. A4 has a small spot mark on it and A6 took a good pounding, if i check A6's continuity to earth would that prove anything ?

Any advise on accessibility to that hidden fuse box at all?

reddandanfireman wrote: ↑Sat Jan 09, 2021 4:35 pm Hi yes I'm assuming so far that the fan is the culprit.

If you have 14.5V at the A4 contact AND the resistor pack is not getting hot, I don't think the fan is the problem.
Scenario 1, fan short circuit. 14.5V at pin A4. Current flows through resistors they get hot. That's not happening.
Scenario 2, fan open circuit. You would get 0V at contact A4, you are getting 14.5V. Fan looking OK.

reddandanfireman wrote: ↑Sat Jan 09, 2021 4:35 pm I was going to take the a4 pin and earth it off as suggested in other posts and see if that makes any movement from the fan.

Yep good idea, just be careful, the fan can draw a lot of current and it's an inductive load so it may produce a significant spark.

0 Volts on each of the resistor wires is not conclusive but its not 14.5V, meaning that the resistors don't appear to be connected to the fan. The voltage drop of 0.19V is less than I would have expected for an active resistor and so I'll call it 0V for this exercise. I'm beginning to suspect the fan speed switch.