Front & rear washers swapped
 

Here's a weird one...my XC90 has been looked at by a couple of garages over the past year because of CAN bus issues. At some point, somebody has done something to reverse the front and rear windscreen washers.

Basically, when I pull the wiper stalk towards me, the front windscreen wipers start but the rear washer operates. When I push the stalk, the rear wiper starts but the front washer operates.

Any ideas what might have been done to cause this?

Cheers!

The pump runs in one direction for front washer, the other for rear washer

They've either swapped the hoses on the pump motor or swapped the wiring to the pump motor

Whichever it is will depend on where the work was done - did you have wiring looms repaired? suspect swapped wires on pump motor (at the CEM, or somewhere to the motor)

Otherwise suspect swapped hoses

The pump motor is at the bottom of the washer bottle

See post #8 here for instructions
http://www.volvoforums.org.uk/showthread.php?t=61892

Thanks Swiss. Really useful info.

Can't think why they'd have gone anywhere near the reservoir but they were playing about with the CAN wiring near the CEM. Maybe they swapped something there, although all wires connect in via multi-pin connectors so not sure how that'd happen.

One garage did the majority of the investigating so suppose I should take it back to them first and see if it rings any bells.

I know this is an old thread but I have just replaced my pump and I get the same thing. Nobody has been anyway near the electrics or ECU, just a straight swap, so the only thing I can think of is the motor polarity is the opposite way around on these cheap units - off ebay for £8. I tried 2 and both the same.
What I can't figure out is if I swap the pipes over you would think that would fix it, but then the near one works both ways and the front one not at all....very confusing!

This is just a guess

How many pipes are there?

1 - pick up from reservoir

2 - output to front

3 - output to rear

If you are swapping the pickup from reservoir and one of the output pipes it'll likely run "back-ass-wards"

Cheers

Dave

The XC90 has a single washer fluid reservoir which has three pumps running from it. The pumps actually plug into the washer bottle directly via large rubber seals. The washer bottle is the most complicated piece of plasting forming imaginable and is behind the front bumper in the o/s wheel arch.

There are two small pumps that are identical and operate the rear window and front windscreen washer jets. There is a larger pump for the headlight washers.

If the bottle has been removed it's an easy mistake to either connect the wrong pipe or wires to the two smaller pumps and transpose their operation. Note that if you remove only the front bumper and do not remove the washer bottle, you will only be able to see and access the headlamp washer pump which is at the front.

Removing the bottle is easy - if you know how. There are a number of hidden bolts for which you need a socket and long extension. It's a worthwhile job as the pumps have internal filters which on a 10 year + old car are invariably partially clogged and the washers usually work much better after a good clean up. I usually sock the bottle in a strong bleach solution overnight to get rid of the slime.

Note - the pumps are cleverly installed at different height, and the washer bottle has carefully designed compartments so when the washer bottle runs down, the headlamp washers stop working first, then the rear window, then finally the windscreen.

thanks Tannaton, I was getting even more confused for a bit then, but I checked VIDA and it seems that there are two systems - pump part number 9169611 which has one outlet and therefore 2 pumps and part number 31349228 which has 2 outlets which operate with a small valve...I gather the motor spins both ways depending on front or rear to actuate the valve. Mine is the second type so still none the wiser.

Oooerr... the last one I did was a 2004 MY car so I don't know if they were changed later. My own 2003 MY is the same.

I'm not familiar with the other system but I don't see how a pump could work different systems by reversing the polarity - surely that would then suck water out of the pipes and then back into the washer bottle??

If that is the case though then surely you just need to swap the pipes over?

Yes one would think swapping the pipes would do it - this is my conundrum. for info there is a nice youtube clip to how the motor works. https://www.youtube.com/watch?v=qffaF5o_joQ

Thanks - that was most useful. I wonder what MY it changed?