Citroen C5 X7 A/C not functioning (heater blower inconsistency)

[Kupsberg]

Hi all,

I've been suffering some odd behaviour on my C5 which I have been unable to figure out/fix.

Vehicle: C5 2008 2.0HDi, 136hp Stationwagon

I bought the car 19months ago and been driving with it ~50 000km. The Aircon has not worked during my ownership and I've tried to find the cause.

Last summer I brought the car to the dealers to make the aircon pressuration tests and refill. No leaks when applying pressure and there werent that much of old R-fluid left. Same behaviour remained after the service.. When pressing the A/C button on the dash right after starting the engine the aircon compressor starts and runs for ~30s after which the compressor shuts down. If repressed A/C button nothing happens. I've checked this on Diagbox and the pressure rises to 13bar and holds there until the magnetvalve kicks compressor off duty. No faults on the A/C system. I also noticed that I cannot run the slow-speed side of the engine fan on diagbox.

I drove last winter like this as there were no need for aircon. The high-speed side of the fan gave up on february on -30 degrees season so I changed it to a new one. I was sort of hoping this would have fixed the aircon issue (read it somewhere here..) as well but after installation of the fan I ran the diagnostics again and still the slow speed side did not work through diagbox. Yet the high-speed started to work with the new fan.

Does any of you have ideas regarding this? All help is welcome..

Addition to this, the blower fan (interiour) seems to run only quite mildly and sometimes it is offline for even few minutes! I've always thought that it is just how it is in C5's but lately I have started to doubt this.. Could there be a diode or similar burnt which could cause all this? The blower did not blow at all when I bought the car, there was some build up ice in the blower due to prolonged standstill period. It came to life when I changed the heater blowers regulator and has been "working" after this.

Could it be interiour temp sensor or similar?

Best Regards
-J

[Kupsberg]

Hi again! Still suffering from the non-working aircon.

The cooling fans high speed stopped working (again) on my holiday trip last week. As the fan is quite new I looked for the issue elsewhere. A faulty 30A fuse turned out to be the culprit! Changed it and it started working again.

I just went for a test drive while looking at the parameters on Diagbox (laptop). I noticed that the high speed now works as it should, started to cool down after temperature rose above 96°C. (Checked out of the car to see if the fan really blows) This could be seen from "required cooling fan speed" parameter as it rose between 20-45%, the fan seemed to follow this parameter precisely. Also the "Coolant temperature" was shown correctly.

The actual "Cooling fan speed" remained zero the whole time as were "Cooling relay status" as "Inactive" at all times! Could this point to a direction to solve also the slow speed side on the cooling fan and by doing so solving also the issue on AC system?

Could a faulty relay cause this and if so where is it located? I tried looking for it under the bonnet and one relay next to the 30A fuse was a 50a/30a switch relay. (896H-1CH-S-T 001) I tested the resistance between pins 85-86 and it was 90 ohms as the datasheet says.
Or is the issue caused by fan speed not being transmitted to ECU?

Help would really be appreciated!

Thanks
-J

[GiveMeABreak]

Worth a shot to be honest for the price of a relay.

[vallium]

Sorry for resurrecting old thread.

It could be weak compressor solenoid that varies its duty cycle. It seems that it has it, black plug on bottom right

https://kompressorenklimaanlagen.de/en/ ... 11426.html



It's common problem on VAG cars but those don't have magnetic clutch.