Infrared? This guy has a CJ2 thingee, that most of us never consider looking at.
Since you have two ECT's built together, I would have scanned the pcm temp. The PCM and gauge should be reasonable close in temp. Fans don't kick on until at least 216F or if the AC actually requests them on. If your AC system isn't up to par, the request may not be happening. Sounds like you have determined that either the ECT or your cluster gauge is bad.
Please elaborate on the cruise issue. It sounded like he jumped a ground from cruise on/enable over to the fans to make them work when he wanted, which you since removed. You didn't mention much beyond that though.
Likely you are enjoying the lack of plumbing and vacuum lines GM vs Ford. You may notice a lack of inline connectors as well. Takes a lot of the easy clean, reconnect out of the diagnosis.
