OK, Where's the Stinkin' Check Valve...
 

Hello all. The washer system on my S420 has been acting up lately and I could use a bit of help. When I hit the washer button it takes 2-3 seconds before I get fluid from the windshield nozzles. I know there's a check valve in there somewhere but I can't seem to find it! If anyone knows where the washer check valve is on a W140 I'd really appreciate it if you could tell me. Thanks!

Shouldn't be too hard to locate. Follow the hose from the reservoir.
On my W124 it is very close to the w/w/ nozzle (passenger side).