No Heat - W140

[sab]

My '95 S320 has absolutely no heat. The AC works fine and the blower motor and regulator (just replaced) works well.
I looked at all coolant hoses coming and going to the monovalve and can't seem to figure out which ones should deliver water into the valve and which ones should send the water to the heat exchanger.
It also looks as if the valve operates two completely seperate circuits and it just seems so odd that they would both fail at the same time.
I found some info in the archives that the valve goes to the open position if it gets no power.
HMMMM.
I remember it stopped functioning shortly or right after a plastic y-connector on one of the small coolant lines broke and was replaced. That Y-connector is on the driver side in the engine compartment on the firewall.
Could a piece of plastic have come loose and be blocking the water flow somwhere?
I pulled one line coming from that Y connector going to the valve and it has no water coming out unless I squeeze on the main coolant line in front of the engine it then seeps out a bit of water. (with the engine warmed up).
Any help troubleshooting this odd problem would be great, its an anoying problem (even though it could be worse... always hot...), which would not be really nice in the Miami summer.
Thanks and regards,
Sab.