Kitchen sink blocked

[jd_h]

Kitchen sink won't drain. Pipes under sink removed, all clear. Snake used by rv tech did no good. Went out 24 feetonly takes about a quart or so of water to back up into sink. But are clear out much further.
Help. Any tdeas?
Thank you,
J.D.

[LadyRVer]

I had a Montana which had the galley tank drain behind the rear street side tire. Did not know it for 3 months. (Can you tell how much I cook/wash dishes?) Does your monitor panel show a galley tank reading?

[Lwiddis]

Might be good to identify your RV make, model and year.

[newman_fulltime]

find the other grey tank valve and open it

[TakingThe5th]

You might have an air lock. Do you have an air admittance valve that might be defective? Is the roof vent open and clear?

A quick test-while the sink is not emptying, pull the dump valve. If it’s an air lock the sink should start flowing.

[donn0128]

Empty the gray water tank.
How many gray water tanks do you have?