By way of an update, the one lead is indeed the air conditioning, and I believe the other lead is the knock sensor, which has been disconnected on this vehicle prior to my taking ownership.

The alternator issue has seemed to have resolved itself - I had the alternator checked and the output was actually fine, but the internal voltage regulator was questionable and the battery light has been on. For whatever reason, the battery light went out yesterday...

 

both of those are a/c plugs. to is for clutch bottom is for pressor sensor. either someone took the a/c off of it if it did have it or it never did. they dont make seperate harnesses to keep productioin costs down

 

Well that's good to know :-) The truck doesn't have A/C and doesn't really need it since I'm in WI and it only really gets hot for one week each summer.

Thanks - it's good to finally have that resolved.