I am not getting any power to the vacuum valve on pod #4 on my 81 SD. This valve is the one that controls the main air flap in the dash. It functions perfectly when I apply vacuum manually and holds vacuum well but due to the pack of power it does not open.
anyone have an idea why this one would not work while all the rest do?
This is a rebuilt controller so it is functioning correctly as verified in my other car.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique