I’ve just fitted yet another rear wiper motor and thought I’d test it out before fitting the rear hatch plastic ( joy) . It would not run at all. After checking the fuse etc gave up for another day however once the hatch was shut it worked fine. Like the front bonnet interlock for wipers is this the same for the rear to ? By the way what’s the best source of rear hatch  clips ?

That's correct - it's not meant to work whilst open.

Could you tell me where this interlock device is located ?

38 minutes ago, wd20 said:

Could you tell me where this interlock device is located ?

Unfortunately not but hopefully someone else can assist.

It will be the boot lock signalling the BCM that it's not closed