300E Floor Heat Problem
 

My 86 300E has no heat directed to the floor. I know this is a common problem and I have tried a couple of things suggested in other posts.
I tested the servos for the floor heat by connecting their vaccuum line directly to the "input" green vaccuum line. The heat came roaring out of the foot vents.
I took apart the climate control panel and resoldered the circuit board where the switches and connectors attach as well as other questionable joints. There was no change.
I don't detect any vaccuum at port 3 on the valve block and I can't get the floor servos to work when I connect their hose to any other port.
Any suggestions?
Also, if I have to, how do I access the servos to replace them?
Thanks, Paul