Scary scary topic i know, but im in distress. I just changed out the heater core, PLUS went and picked up a new heater box, the previous box that was in it was garbage , the actuators were broke and flaps were damaged, the previous owner did this ...

Here is the problem, I put it all back together perfectly and correct, even the vacuum lines, BUT, there seems to be NO vacuum in the system nothing is functioning, doesnt seem like the a/c kicks on , the flaps do not open or close, no hissing no nothing, the vent doesnt open , im at a loss. I replaced the the heater core, the blower motor and the blower motor relay, I know doesnt pretain to it , but in that I found a broken vacuum line outside that hooks up to 1 single line that comes into the cab, and that one single hard plastic vacuum line that comes in the cab is damaged how bad I dont know, i think its pinched but I cannot tell , there is no air coming in or out of that either ... the wierdest thing is , when the heater and air controls are turned off the engine wants to peter out I mean she drops to 800 rpms and doesnt have a smooth idle , and when I turn the heater controls, she kicks up to 1000 rpms and idles smoooooooooooth this is all new to me i've never encountered anything like this, this is a 6.2 liter diesel 1983 c30 dually standard cab.

Any helps or opinions are always very much appreciated , I dont know if there is a main line into the system or now, but any direction would help thank you all much ,

Mike..