Rear Wiper Problems

[iainst26]

Had a look through the forum at the numerous rear wiper problems but none seem to be the same as mine.
I replaced the wiper motor with a second hand unit a while back as mine stopped working completely.

There is also problems with the replacement wiper, it does no spray and it does not work of its own controls, the only time it does come on is if im spraying the front screen.
Im sure when I checked fuses/relays everything was ok. Im asuming it could be the 2nd hand unit, but could also be the wiper control.

Any Ideas.
P.S Car is a 2000 X A4 Avant

[iainst26]

EDIT: Hose reconnected at rear to provide water, Wiper wipes when pulled to wash but doesnt work on first click if that makes any sense.

Also rear wiper comes on when washing front screen.

[mumutley]

The wiring for the wiper motor goes through at the tailgate hinge point.
If fuse good and rear washer pump works.
Check this wiring
It gets brittle with age.
I had Audi 80 estate mine went the same way
I removed rear inner roof lining, tailgate lining. Got to both side of the wiring harness and replaced all the wires that run through the rubber at tailgate hinge point
Cant remember exactly but I needed approx 6 or 7 different colours and approx 24 inches of each, soldering iron and heat shrink to protect and insulate all joint made.
Cut one wire at a time, say in side roof solder new wire to wiring loom, other end of new wire to end of old wire then go to tailgate find same colour wire and pull gentle new wire is pulled through by old wire. Cut old wire inside tailgate and solder new wire in. do the same for all, remember to put heat shrink on all soldered areas.
It takes a couple of hours from start to finish but all works as it should in the end
This sorted mine a treat