Stevebfl...

[ChinaClipper]

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....

[stevebfl]

Well, I don't keep this all in memory so I had to wait till I could look it up and be sure.

The water valve vacuum comes from the switchover valve (elctrically operated vacuum switch). It is part of the switchover valve group. Source vacuum (for switching) comes from the engine and I didn't look it up.

The decision to switch vacuum to the heater valve and the electrical control of the switchover valve is done in the pushbutton controller based upon various inputs: evap temp, outside temp, feedback pot, and incar temp.

I would check your source vacuum to the switchover valve group.