Update: Nevermind, I've got bigger issues.

I popped the cap off the degas bottle and noticed the coolant is full of sediment. I called the guy who did the work on the EGR cooler/oil cooler and he said the flush must have knocked some junk loose. He recommended putting a Bulletproof HD package on the truck and calling it a day. I pay for the package and he'll warranty the installation ... sounds fair to me! He also told me to leave the fan clutch/thermostat/coolant filter for him to install while he's doing the work ... what a gentleman!

 

Highway speeds, especially not towing, aren't going to show a bad fan clutch. There's plenty of air moving across the radiator, at that point the fan and clutch are pretty much just along for the ride. It will show in slow city traffic or pulling loads with high engine load and relatively low speeds. I assume your A/C was working fine at highway speed but not idling or slow speeds. You didn't really make that completely clear to me. If that's the case, you may need a new clutch or it could be just in the tuning. The 6.0 has an electro-thermal (or something like that) setup to engage the fan when the PCM thinks it needs it and to keep it more free when it thinks it doesn't. This keeps down fan noise and helps a little with fuel mileage. It's possible that you may have just needed to check your harness connection to the fan clutch. It could be frayed or cut. Look up the "blue wire mod", you can try that and know pretty quickly if the clutch is shot or not. Your temps look fine, even a tad low in the mornings.

The fan doesn't automatically come on with the A/C. Like I said, it's all up to the PCM. Several variables are taken into account to determine just what percentage the fan is activated.

 

I didn't have cold A/C; highway or at idle. Warm air was coming from the vents. The A/C tech recharged the unit and it appeared to get cool, but he then checked the fan and said it was not working correctly with the A/C. He feared damage would occur without the fan being addressed, so he unplugged the compressor.

 

He probably doesn't understand how the 6.0 fan works. Besides, it's not going to damage the A/C if the fan isn't working. Assuming the system is in proper working order, all that would happen is it would kick out from high side pressure. I'd plug it back in, but then again I'm in Florida. It's required.

 

Yeah, I wondered, myself, why it would affect the A/C. I'm in Southern California and, although it's been in the 70s today, it gets pretty uncomfortable off and on. I'll plug it back in and see how it runs. Thanks for your input!