Peugeot 206 - Beeping alarm & flashing interior light

[PG]

PROBLEM: X reg 206. Sometimes when driving away a repeated beeping is heard and the courtesy light flashes.

CAUSE: The car thinks one of the rear doors has not been closed and is alerting me to it. I have to open the door & close it hard and the alarm stops.

SOLUTION: Does anyone know where I should start in an attempt to fix this?
There must be a loose connection or poor contact in the electrics of the door but I don't know what to look for.

 

[keyplayer]

I would start with the courtesy light switches, I would have thought these are used to ascertain door position. Some WD may help to loosen them up.

 

[PG]

I couldn't see any switches in the doors that control the courtesy lamp.

Other cars I've owned had a sprung switch near the hinge of each door that gets pressed when the door is closed, thus turning off the interior light.

I couldn't find any switches ??

 

[al-yeti]

its probable on the catch in the inside, small metal strip of metal