Citroen XM Forum

...the sensor is located in the right rearview mirror, it is not difficult to get to it, in order not to tear everyone's hair, I had to cut the cables on the rearview mirror itself and solder them when everything is completed.
..I removed it with a drill, made a place for a new one, filled it with hard plastic.
...at the end, everything is sealed with two-component glue.

...the reading is correct, checked on the temperature read by the sensor on the VW Passat.
...that sensor is also connected to the operation of the air conditioner, before when I turn off the car, after a certain time when I start the car, the air conditioner goes into AUTO mode, it did not want to keep the previous setting, now it keeps everything as it is set.

Another problem also solved with costs of 1 ev


...a very simple and easy solution, you only need clamps for electrical cables and glue everything with two-component glue.
...locked

...the only thing left is to find other screws, they should be Torex, they look nicer, although I can also paint these with a black felt-tip pen.


let me mention, you have to shorten the screws to 5-4 mm so that they are in line with the plastic so that the button can go down into the door, you will see for yourself how much everything needs to be adjusted.

A couple of very cheap solutions there, Gasa, how do you know the resistor value is correct for displaying the correct temperature?

You can buy the sensor for not much and the lock buttons with screw fitting, instead of the original clip type, if you look for buttons for Citroen Beverly or Elysee.

...I saw this from an XM owner who posted pictures and details about the resistor on the Serbian forum, he deals with electronics and came to the conclusion that this value of the resistor is needed. His accuracy check was the temperature on the two Xantias he has, so the exact resistance of the parts he set as a sensor on the XM.
...I will see how the sensor behaves, if there are any problems again I will buy the original one.

...I know there are, but until those parts arrive in Serbia, a lot of time will pass, this is how I solved the problem in an hour, and I have original buckles, not Chinese ones.

Gasa wrote: Mon Feb 20, 2023 9:11 pm
...that sensor is also connected to the operation of the air conditioner, before when I turn off the car, after a certain time when I start the car, the air conditioner goes into AUTO mode, it did not want to keep the previous setting, now it keeps everything as it is set.

The outside temperature sensor (906) isn't connected to the climate control panel, only the R/h dispaly.
I suspect your issue with the climate control panel resetting is due to losing +12v continuous supply.

...I don't know, I'll check, I thought it was also connected to the operation of the air conditioner, why would the air conditioner remain without 12V, through which relay is the air conditioner control powered?

Interestingly, I can't see an unswitched live supply, so presumably it must be storing settings such as temperature and direction of airflow in an NvRam.
Unplugging the unit, would confirm that.
Alternatively, it is receiving power from the cooling fan control module, via the white 5 pin connector on B2.

The two relays are 805, compressor cut off and 821, Air conditioning additional relay.

..again a problem with temperature measurement, obviously it's not a problem in the sensor, I also put the original sensor and the same problem happens with it , what does the temperature read, where does the sensor send the signal.
...the resistance of the sensor I made. ...the resistance of the sensor I bought.

Your home made sensor is fine, the resistance is close enough to the original one to be Ok, but adding another 120 ohms would make it very close indeed.

The sensor feeds to the R/h display on pins 5 and 6.

There are two intermediate connectors, the 2 pin brown one in the door lining and the black 23 pin one at the door hinge, pins 3 and 4.
I suspect the door hinge connector is making poor connection, probably due to water ingress.

The display showing --- indicates open circuit.

Gabors' circuit diagrams.
download/file.php?id=9711

The external temperature sensor is covered under "Trip Computer"