Hey Steve, I am troubleshooting my climate control sys. and found that I have no vaccum going to my water valve. I pulled the line and ran the climate control sys.; high temp, low temp, A/C and every mode in between and got nothing in the way of vaccum. I blew into the line and it appears that it isn't broken. The vaccum switching between defrost, vent etc seems to work. It is the temp that is stalled @ hot. What modulates the vaccum to tell it, the water valve, to open? Thanks for your help....