Ok guys ive been trying to diagnose shutdown issues on a '89 "308D" mercedes van

ive located the vacuum shutoff valve on the injector pump and the two brown pipes on the ignition switch, but im unsure how to go about diagnosing the problem

im assuming one of the pipes comes from the vacuum pump itself? possibly off the brake servo line? runs to the ignition switch then onwards to the vacuum cutoff?

the cutoff valve is mounted on the rearmost face of the injector pump, but ive also noticed there is a black valve with a pipe connected to it on the top of the pump at the same end? any gen on what this does?

i guess i can test the shutoff valve by applying a vacuum to it, but in the absence of a proper vacuum pump is there any other methods i can use? will sucking on the pipe produce enough vacuum to shutoff the motor?


also ive noted the van has no hot air blowing thru, while inspecting the ignition barrel i found a black valve with 2 large pipes going to it and a wire connected to the heat slider on the dash, the dash slider moves the arm on the valve back and forwards but even with this all the way to hot the air never seems to get warm, ive not checked if the pipes to this valve are getting warm but any ideas on that issue?

cheers

Kevin