David(4x4 kiwi) instructions seem to cover it really. in my case the door ajar was working intermittantly so i guessed it was something minor. I took the door card off and managed to clean and spray a large amount of WD40 over the lock mech on the far right of the door. if that does not work you might need to take the whole lock mechanism off and give the door ajar switch a better clean and inspection. dont forget to give the whole door a good clean out whilst you have the panel off. Being a big believer in wd40 i gave it all a vacuum out and i sprayed a load into the botton of the door to keep the rust off...hope you have the same luck Dave

PS i also re-polythened the door with fresh polythene to re-seal the door