V70 Rear Wiper Not Working, except for a tiny bit.

We have a 2001 V70 and the rear wiper doesn't come on when requested.
However, it is parked, the fuse is fine, and when I've fiddled about
with it/slammed the tailgate / forced the wiper out of park it has
sprung into life a bit, and returned to park.

From googling this group I'm suspecting the wires that get bent every
time you open & close the tailgate are failing, but any other ideas of
likely suspects? Or sensible diagnostics?

TIA

Dz
London

 

I forgot to ask: Is there a logic / relay whcih stops the wiper
working when the tailgate is open?
This appears to be the case, judging from the times I have actually
got the wiper to work, but it may just be further evidence of a
cracked wire near the hinge.

Dz

 

The rear wiper on my '03 V70 went the same way last year. It turned
out to be road dirt/gunk within the sleeve (which passes through the
glass) causing excess friction on the wiper shaft. As the gunk builds
up over time, the motor runs out of torque to overcome the friction.

In my case, the cure was judicious use of lubricating oil to try to
flush out as much of the gunk as possible, together with a bit of
wiggling to free-up the shaft. It's been working perfectly ever since.

I did attempt to strip the mechanism off the tailgate before trying
the above method, but gave up due to developing a crick in my neck.

Cheers, Steve

 

Thanks for experience Steve, but after further investigation:
If I switch on the wiper then open the tailgate and then close it
slowly, when its about 1.5' open the wiper comes into life. If I hold
it there it continues to work, mainly, but if I continue closing it
stops (without parking).

Therefore this leads me to suspect a broken wire near the hinge. Both
hinges have wires running along them - any ideas whether its left or
right side, or colour coding?.
I'm suspecting that the break itself is well inside roof, and that
this is could be a time-consuming job.

Dz

 

Certainly sounds like a broken wire. Afraid I can't help with the
wiring loom details though. :/

Cheers, Steve

 

It sounds like your problem is definitely a broken wire in the hinge.
The wiper motor has a switch internally that creates the parking place
for the wiper. An old problem that I haven't seen on more recent Volvos
was grease from a worm gear in the wiper motor getting on the switch
contacts and fowling up everything including the parking and general
operation. That was very easy to fix by taking the cover of the gear
mechanism and wiping off excess grease since the switch was an simple
open contact on a rotating plate.