Tailgate gone crazy

[Emuu51]

My 2010 C5 Estate has started having weird issues. When I select reverse, the rear wiper activates. Often, even in forward, it will only stop when I activate the rear wiper switch! The reversing lights don't work. The tailgate more often than not, will only raise part way and stop. It stops at different locations depending on whether I use the remote or the button on the tailgate. Often, when the tailgate gets activated, the rear wipers start to work, then, they'll stop and the inside lights will activate. The faults are different if the headlights are on or off. Help.... Please.....

[GiveMeABreak]

Most likely issue is the area where the loom enters the tailgate at the top - it's a weak point where the wires are under strain and can cause intermittent issues where they start to break. That's the first place I would focus on.

[Paul-R]

How old is the battery?

But yes, the loom is notorious for breaks between the bodyshell and the tailgate..

[Gbro8936]

I had a similar problem with the c5 x7 I used to own as givemeabreak suggested the wiring loom in my case that was the problem a simple fix there was a broken wire coloured white just looped a new piece between the snapped ends taped up the loom with insulating tape job done

[Emuu51]

Well, after noticing that the tailgate responses differed with state of charge of the battery, I've changed it with a new one and now the tailgate is consistent in going up and down. It does however, still have the issue of no reverse lights and the rear wiper coming on instead when I go into reverse, so now to work out how to isolate the faulty cable. How did those of you with similar issues identify the broken cable? I don't expect it will be a clean break including insulation.