Rear door open warning

[only1pearson458]

Hello,
I have managed to save money by asking questions here, so hopefully someone can help me. This is concerning my 2008 Sovereign estate
A warning message on the dash tells me my drivers rear door is open. I have checked and it is correctly closed. I have locked the car with the key. The car horn beeps warning me the doors not shut. The interior light stays on, and I am hoping will go off eventually. Is they a cheats way to fix it, I have sprayed wd40 in the latch part of the door, someone on another forum suggested and will leave over night. Really don’t want to have to poor out another £250. To get a new mechanism fitted.
I appreciate any support.

[steve_m]

It will probably be the sensor playing up but could the battery playing funny buggers.
I found this elsewhere, on another X Type forum.

Door switches short to ground when the door is open and are held open circuit when the door is closed to check the switch simply remove it and tape up the cable connecter so it cannot short to the bodywork. If you still show the door open then follow the wire back along its run to see if you have any damage, be critical of any place it can flex

[only1pearson458]

Thanks for taking the time to reply.
For now I’m taking a punt and ordered a new door latch and will try and fit it my self.
Watch this space. Lol

[Astromorg]

I fear Steve has been misled! The Door Ajar microswitches - one per door - all go open circuit with the door open and switch to Ground when the door is shut.

The OP asks if there is a method to cheat the system; there is indeed. The wires to the four door ajar switches all come from the General Electric Module (GEM) which is positioned above and to the side of the accelerator pedal and is easily recognized by its five different coloured connectors. The particular wire to the driver's side rear passenger door is a Yellow wire in the lefthand, Grey connector.

In the bottom row of wires in this connector there are two Yellow wires. The one you want is the lefthand one, a small gauge wire. There's a Green wire on one side of it and an Orange one on the other.

If you splice a wire into that Yellow wire and connect it to a convenient ground point, the dash will see the door as shut in all conditions until you remove the wire.