You or I would have to look up the diagram in the service manual to find out. I don't remember for sure, it likely activates a solenoid valve to turn on/ off the vacuum advance line to the distributor.
I have a paper 75 or 76 manual 'if I can find it' LOL
Here read this
http://www.mymopar.com/downloads/mtsc/326.pdf
came from here
MyMopar - Mopar Forums & Information - MyMopar Tools/Reference
Click the link "
Master Tech Service Conference Library"
MyMopar - Mopar Forums & Information - Chrysler Master Tech Service Conference Library
and select "model year"
There's a video and this pdf