C4 heater/air con not working

[martinbear]

So after reading this thread when my blower stoped working i went ahead and wired in the shunt
And yay it worked
For about five minutes
Then it stoped
Back to square one, no blower , no recirc lights and no aircon light of action
I'm flummoxed which is not unusual when throwing spanners at myC4

[GiveMeABreak]

If you have no lights on the control switches, check the fuses again, but you may have a faulty control panel module.

[GiveMeABreak]

If you post or PM your VIN, I'll take a look at the parts for your Pic - as there are a variety of units available.

[GiveMeABreak]

Marc just bought one of these c4 for wife to run around in its a 2005 but heater only works on 4 assuming its the resistor are they hard to get at ??
Cheers

I've only just spotted this - must of missed it! Did you get the issue resolved?

[Tevz]

Same problem but for a xsara
You able to provide for that also?

[Neil Davies]

I'm another one who has stumbled across your forum while searching for help on the infamous C4 heater!
This one belongs to a friend, it's a 55 plate 5 door, and the problem is much as petef describes in the first post - the four speed blower switch doesn't work (most of the time, every once in a while it kicks in!), the recirc and air con buttons don't work but the heated window one does. I started off checking the fuses, and all of them seem fine. Then we found a heater control module on ebay locally and cheap, so we changed that, but no joy. I've checked the blue plug on the back of the module for 12V supply and continuity - the thick red wire is the switched 12V, the next four on the bottom row (yellow, green, pale blue, white, going from thin to thick) I assume are the four speeds on the blower rotary switch. Weirdly, these all seem to be connected ! When I use the multimeter with the buzzer function to check for continuity, it doesn't matter which of the five wires I connect to, there's a buzz! This leads me to suspect a short circuit elsewhere in the circuit. Is this a symptom of the resistor pack failing, or am I barking up the wrong tree entirely?
Thanks in advance for any and all help!
Neil

[petef]

I strongly suspect that your problem will be solved by the 'Bridge Wire Trick' as detailed in this thread. I too had 12v getting to the controls but the heater blower and air con would not work. The fused bridge is easy to try and costs next to nothing so is surely worth a go.....?

[Fayez]

Thank you,

I'd appreciate that.
I would rather establish that it is indeed the fuse box before I incur any unnecessary expenses.

Are you suggesting bridging the circled wires? IMG_20171109_204406.jpg

Hi Justin

Can you help me do the same to my car ?
Just want to know which wires to connect and how to identify the + and - on it?

Appreciate your help

[Justin_Brown]

Hi Fayez,

Without cutting the circled wires I simply used a stanley knife to remove about a 7mm section of insulation on each of the two wires. After which I soldered in an inline fuse holder and taped up each of the soldered connections with electrical tape. (If memory serves I think I used a 30A fuse)

+/- isn't a problem as it is only a single pole and all you are doing is bypassing the relay switch. I have subsequently replaced my faulty BSI unit as I started picking up many other strange electrical issues. But I made use of the above fix for more than a year with no problems.

[Fayez]

Thanks Justin
I appreciate your reply.
I did as You said but nothing changed and I am now pulling my hear for this fault .
It’s frustrating specially when you try everything.
Now i changed control unit and resister and fuses and checked the motor working good.
Now by doing what you explained you bypassed the fuse board and if the fuse board not connecting the + to the blower this method won’t work.
I am just thinking if I get a wire from the + on the battery and connect it straight to the new fuse I installed after disconnecting the cables from the fuse board will it work ?

[C4_VTS_PL]

Hi Fayez,

Without cutting the circled wires I simply used a stanley knife to remove about a 7mm section of insulation on each of the two wires. After which I soldered in an inline fuse holder and taped up each of the soldered connections with electrical tape. (If memory serves I think I used a 30A fuse)

+/- isn't a problem as it is only a single pole and all you are doing is bypassing the relay switch. I have subsequently replaced my faulty BSI unit as I started picking up many other strange electrical issues. But I made use of the above fix for more than a year with no problems.

Hi Justin,

I did what you said and my blower works...randomly.
I need to turn it off before I turn off the engine (every time) - If I don't do that, the blower wont work when I start the engine next time.
It only works on the 4th gear during start-up/ignition and stops when the engine already works.
Sometimes, when I turn the heater/blower off before the engine, it works after next start-up, but it's a lottery.
Any ideas, what I could have done wrong?
(Sorry for my English - not my native language).

Thank you!

[Justin_Brown]

Hi C4_VTS_PL,

I'm assuming the blower controls fitted to your car is manual and not climate control? If the above fix didn't work it may be worth checking the condition of the blower motor resistor as well as bench testing the blower motor itself with 12v.

Regards,

[C4_VTS_PL]

Hi C4_VTS_PL,

I'm assuming the blower controls fitted to your car is manual and not climate control? If the above fix didn't work it may be worth checking the condition of the blower motor resistor as well as bench testing the blower motor itself with 12v.

Regards,

Hi Justin,
Thank you for your answer.
I have an automatic AC. Your fix worked, the blower and the resistor are ok, I have checked both with multimeter. The problem is when I turn off the engine with the heating/AC turned on, it won't work after next engine start-up, it just blows on its full power during ignition ,(2-3 seconds).

[admiral51]

I had the blower issue on my 55 plate C4, i did the bridge trick and all is still well over a year later.
Mine is not the Auto A/C but manual 4 speed blower but by doing the bridge you bypass the relay, this relay is meant among other things to avoid having the blower kick in when the ignition is switched on.
If you switch the blower and A/C off before you turn the engine off does it behave as normal when you start the engine and turn the blower on ?
I think you may just have to live with the limitations provided by the bridge trick, with the A/C and Blower on when you switch the engine off there may be an ECU that has not shut down properly and when restarting the engine it shuts everything down, only guessing just trying to think logically.

[C4_VTS_PL]

I had the blower issue on my 55 plate C4, i did the bridge trick and all is still well over a year later.
Mine is not the Auto A/C but manual 4 speed blower but by doing the bridge you bypass the relay, this relay is meant among other things to avoid having the blower kick in when the ignition is switched on.
If you switch the blower and A/C off before you turn the engine off does it behave as normal when you start the engine and turn the blower on ?
I think you may just have to live with the limitations provided by the bridge trick, with the A/C and Blower on when you switch the engine off there may be an ECU that has not shut down properly and when restarting the engine it shuts everything down, only guessing just trying to think logically.

Hi admiral51,

It makes sense.
Sadly even if I turn the A/C and blower off before I switch the engine off, sometimes it doesn't behave as normal after next engine start - this is why I am confused. It just works randomly. Maybe it's a faulty relay?
I think I'll just have to buy a BSM module (maybe will find a used and working one).
Thanks!