Be careful when you remove the harness connector. Those things get brittle with age and break easily. Also, while you have it apart, thoroughly clean both sides of the connector with contact cleaner and a mechanical scraping device of some kind. They are probably in some stage of corrosion by now. I have been told that an air regulator is usually only good for about 80,000 miles before it needs to be replaced so don't be surprised if cleaning it up doesn't make it all better.
Also, while you have the air regulator off you ought to pull the heating plate under it and replace the hoses that go to it and ensure the ports in the plate are open and free from debris.
One other thing to check from an operational standpoint is to put voltage to it, and make sure that it opens. If it doesn't you can pull the bi-metalic spring, and recurve it. I did it to mine, and it was like new. Let me know if you need more info.