1972 Duster Heater Control Unit - defrost question

Hello,

The control unit has a broken nipple and I can't find a vacuum diagram. I am wondering if anyone knows what the broken nipple was for and if it is for AC only or if it will prevent the defrost from working assuming I can find a way to reattach the temperature control cable to the adjustment lever. Thanks in advance for any help you can provide.

Go to MyMopar and download (free) the 72 Plymouth chassis manual (factory service manual). Down through about 24-50, and especially page 24-63

Several of the manuals over there came from the guys right here