EGR Time Delay/Electronic Speed Switch

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