I said "EGR solenoid" earlier, but I meant the purge solenoid valve - located on our trucks just below the purge cannister... an extra one of those should work just fine.

The aquarium valve might work for air flow adjustment..... or I could adapt a carburetor needle and seat into a small box. The best arrangement might be a fixed opening, though - easy enough to make by plugging a vacuum line fitting with epoxy, then drilling the epoxy filling with the correct hole size..... trial and error notwithstanding, it might be an easy fix.

First, I need to get the A/C compressor circuit working, though.

Frank