C8 Heater and Aircon

[MrC8]

Model: C8 2.0HDI YR 2009

Wondered if anyone had any experience of heater and A/C issues with the C8, here is the fault which has just started:

Heater controls goes from 14 - 28 degrees at 28 there is heat coming out seems OK temp, but always difficult to remember if it is/was as hot as always.
Drop the temp down by 1 degree to 27 and it goes cold, not even a hint of warm and way too cold for a January day. Go all the way to 14 and is still super cold with the A/C on, 27 seems just as cold as 14.
Move from 27 back to 28 and heat again.

Also appears to have happened at the same time is that if you have the temp at 28 and A/C OFF the car screen and windows steam up straight away, only way to clear is to put the A/C on.

Everything else seems ok, the AUTO control works the manual fan control is ok and buttons for demist etc....

Thanks for reading and in advance for any replies, hints, tips etc....

Cheers for reading

Andrew

[h2ocooler]

Sounds like the internal temperature sensor(s) have failed so the system thinks the cabin is up to temperature, Not sure where it is located.
As far as the steaming up is concerned, most cars are now meant to have the AC on all the time to dry the air out, the steam you are getting is just from the evaporator as it warms up as it will be covered in frost when the AC is working.

[Hell Razor5543]

Does your car have the ability to show the outside temperature? If so, is it accurate? I have heard of a case where a failed outside temperature sensor caused an issue with the internal temperature management.

[MrC8]

Both interesting replies and thank you.

Temp sensor is worth looking at and will investigate. Prior to this issue I've not had a problem when steam when turning the a/c on and off. The majority of the time I've never even used the a/c, apart from in the summer.

Outside temp is also a good point and yes it does display it. It has gone wrong, I've had 2 C8's and both developed the same issue with the outside temp reading very high. The previous car did it but never developed a fault with the heating. The outside temp reads around 50C too high! Yesterday it was reporting it was 61C!

I've done a BSI reset but this didn't fix it. I do remember reading the the sensor is in the drivers(?) mirror housing. Someone may wish to correct me on that.

Many thanks for taking the time to reply.

Andrew

[Hell Razor5543]

I cannot confirm where the sensor is, as I have no personal experience of the C8. However, if you check the underside of each wing mirror you should find a little dome on one, and that is the sensor. I cannot say how easy it will be to replace it.

Just checked on docbackup and the sensor is in the passenger wing mirror, part number 6445 F9, and it looks like it plugs in somewhere (as opposed to being soldered in place).

[1997V6]

I had a similar problem with my C5, only had heat when set to 28 and external temperature gauge gave wrong readings. Checked with Citroen dealer and outside temperature sensor in L/H wing mirror is linked to climate control. Problem fixed by replacing wing mirror sensor. Easiest way to repair was, remove faulty sensor, cut wires to it within wing mirror, fit new sensor and re-solder new wires to existing.

[MrC8]

Brilliant. Thank you again for the replies. I will replace the sensor and see where that takes us.

That's exactly what the Internet was invented for...sharing of knowledge.

Thanks again.

Andrew

[MrC8]

I cannot confirm where the sensor is, as I have no personal experience of the C8. However, if you check the underside of each wing mirror you should find a little dome on one, and that is the sensor. I cannot say how easy it will be to replace it.

Just checked on docbackup and the sensor is in the passenger wing mirror, part number 6445 F9, and it looks like it plugs in somewhere (as opposed to being soldered in place).

Checked the car and on the passenger mirror there is a small hole where it looks as if a sensor goes, on the drivers there is a dome which is clearly a sensor ?

[Hell Razor5543]

OK, that would suggest the sensor is on the driver door mirror.

[1997V6]

OK, that would suggest the sensor is on the driver door mirror.

It's definately on the L/H side mirror on my C5 Mk1 (2002), with a hole on the R/H side mirror .

[MrC8]

Fixed! New external temp sensor fitted. It was in the drivers door mirror. Easy job to do.

Thank you for your advice, it's really appreciated. I'll go pop the kettle on for a cuppa for us all!

Andrew