Fan heater continues to blow when ignition off

Hi there, newbie here asking a question on behalf of my father in law.

He has a 56 plate 1.1 petrol C3.
Discovered the car had a flat battery on Sunday, got it jump started etc and all was well.
However he has discovered what caused the problem - when the ignition is switched off, the heater fan inside the car continues to blow. If he manually switched it off that's fine it goes off, but where it should switch off with the ignition it isn't.
All other items like radio etc are switching off when the radio is killed but not the fan heater.

Have searched on here and there seems to be lots of info when the heaters aren't working, or only work on one speed but can't see anything for this.

Anyone experienced this and can help out?

Hi bobbyg, you may have something like the one in the link below, with melted wires?

questions-about-a-citroen-c3-not-relate ... 3-s20.html

Surely if there were melted wires the fan wouldn't be able to be switched on and off through the various speeds with the control knob?
That part works fine, its just that when the ignition is switched off it continues to run.

I reckon that whatever links it up to the ignition power, wherever that may be, is at fault but don't know what it would be?

The blower fan is controlled by the heater control panel which is fed by power from the BSM (engine bay fuse box) and doesn't go via the ignition switch.

I would be looking at a damaged BSM (engine bay fuse box) to cause this....

If you pull fuse F8 in the BSM, does the fan stop?

Thanks for that suggestion - I will check it out and report back!

Its actually fuse 18 in the fuse box that is for the blower - when I removed that the blower stopped, and re started when I inserted back in.

So what does that tell us?

bobbyg wrote:Its actually fuse 18 in the fuse box that is for the blower

F18 looks like for cars without a/c or climate control, and F8 is for cars with climate and air con, thanks I will take a look at the diagrams on the site and update if necessary, but they did change in 2005/2006, so my diagram may not be completely up-to-date.

bobbyg wrote: - when I removed that the blower stopped, and re started when I inserted back in.

So what does that tell us?

It tells you the relay in the BSM is in an energised state. (F18/F8 powers the relay contacts) That could be because the computer signal to the BSM says 'energise', but it could be that the relay has just melted its contacts together. A computer signal fault would probably clear when the BSI goes to sleep, and the fan would stop....

So far, changing relays in the BSM hasn't gone well and its recommended a replacement unit is fitted if you suspect the relay. You can find a Complete Citroen BSM unit from here, look for similar numbers from a similar year, different Citroen models BSM also fit the C3.

I would be worth looking into what killed the relay, if is actually faulty.

If the relay is in a permanently energised state, you can control the fan from the fan control panel in the car and switch the fan off, but the computer can't switch the fan off if the fan control panel in the car say 'on'.


Is yours A/C, climate control or neither? and please confirm yours is 2006 (late model) car. Thanks!

Hi there, it is a 56 plate non air con car. That's useful info you have given me.

Where is the relay that I should be looking for?

bobbyg wrote:Hi there, it is a 56 plate non air con car. That's useful info you have given me.

Where is the relay that I should be looking for?

Thanks for confirming the year etc.

The relay is part of the BSM (the fuse box in the engine bay). The relay is not something you can see, inspect or change, but appears on the wiring diagrams. Some BSM can even be virtually impossible to open without damaging it, but others open up more easily. Its been attempted before and repairing these BSMs have not gone well, hence the recommendation just to change the whole box. Match one from a similar spec car, that looks the same with similar a similar part number.

Thanks for that info - can I just clarify if its the fuse box in the engine bay or the one in the glovebox area that I should be looking at changing?