Heated rear window wiring

[monitormagic]

Hi I've got a m59 Berlingo forte multispace 53 reg. I've got no voltage reaching the rear demister but I do have the heated mirrors working and I think these 2 things are linked at the same fuse which tests ok. The wires for the rear demister come out of the tailgate and disappear inside the body of the car. Has anyone got a wiring diagram of harness diagram I could follow ?   It's a 2l hdi. Thanks

[Zion]

I don't have diagrams for the M59 to hand but the issue is probably a broken wire inside the rubber boot that links the tailgate to the body. Worth peeling it back and look for snapped cores. Join anything broken and that should solve it. Ideally best to solder or crimp and insulate the break.

With the flexing over the years, it's common for one or two wires to snap inside the flexible boot carrying the wiring for heated screen and wiper.

[monitormagic]

Thanks for your reply but I've checked the wiring under both sides and it's perfect

[Zion]

Even inside the rubber tube?

Anyway it would be easy to see what colour the wires are at the window element end, then find those two under the headliner at the back.

Remember too, the switch will engage a relay and won't carry the heated window current directly so it could be the relay has failed instead. You would then get 12v at the heated window switch but not at the window.....

I don't have an M59 manual now but in any case the relay will be built in to the BSI module and not simple to identify or replace.

Can you hear a click from below the steering wheel area when switching the heated window on?

These relays are known to fail and require quite a strip down to desolder and replace if you can even identify the right one. They aren't marked or documented.

[ffrenchie]

If the mirrors are heating up it sounds like a fault in the rear element or the wiring to it. Can you connect 12v to check the element or run a continuity test on it and narrow it down to the wiring ?

[monitormagic]

Thanks all I found the problem. I had someone hit my passenger rear quarter about 2 months ago and the accident had ever so slightly pulled a green multiplug apart but it was enough to interrupt the power. One again I thank you for all your help.