Rear windscreen washes when stalk pulled forward?

The switch contacts get fouled up and require cleaning, otherwise it's a very expensive job to replace the wiper stalk switch assembly. Found this on an Audi forum (there's a html link in one post to an S5 switch overhaul but I'm not sure if it's the same procedure as a Q5) -
Wiper Switch Audi A5 Forum Audi S5 Forum

You press the washer stalk to operate the rear washer but quite commonly the washer jet blocks up and will not release water.

You need to use a pin to try & unblock it. If this doesn't work (and it probably will not) you need to remove the trim on the inside of the boot, unclip the high level brake light & wash out the nozzle with warm water.

Unlikely it's the stalk if both stopped working at once more like a fuse or the pump

open hood check to see if hoses are hooked up they come off from time to time , see if any fluid goes on the ground when useing

Remove cover from rear wiper arm (it is covering the wiper arm nut) gently ease off the plastic moulding in the middle of the nut try squirters if water is coming out unblock the water jet holes in the plastic moulding

First and for most, check the fuse, that has probably burnt out. I am pretty sure that is the issue. Next if after finding fuse in panel , and replacing it, still don,t work, then next step would be checking washer/wiper motor. Thanks, please let me know, mike from fixya

I would check the relay by pulling it and swapping another in it's place but it is probably an issue with the stalk

If the 'flash' pull works it will most likely be the switch in the stalk (lever). It should be an easy enough part to get.

Over a period of months the flow from the washers on our 2003 307 gradually reduced until there was nothing although the bottle was full and the pump could be heard. After removing the right front wheel and the inner mudguard liner the bottle can be removed. The pump unclips from the bottle. The pump has two outlet ports. Clipped into the ports is a small cylinder with spouts for the front and rear washer hoses. The pump runs forwards or backwards for either the front or rear wash. Inside the small cylinder is a rubber cylinder in a plastic tube which is a shuttle valve to isolate the two circuits. Over time the rubber cylinder had expanded in length and blocked both circuits. I shaved 1 m.m. from each end and now it works like new. You need to be a bit handy and be careful not to break or bruise any plastic surfaces. A Haynes manual is some very basic help.

Hi

Sounds like an earthing problem if you have already checked the relay and fuses. although if they are both controlled by the same stick on the steering wheel it may be lose or have packed up completely. Like you say its strange both are not working.

Start at the route of the wiring to the wipers and trace it all the way until you find the fault if its not the stalk!

hope this helps