One of our friends is the former service manager at a Ford dealer (quit last year). She used to tell me how the techs would bitch and complain any time there was a computer issue about how they "aren't computer techs, they are mechanics, they don't know what to do with computer related issues," blah blah. My response was always "First, isn't Ford supposed to be training their techs? Second, if they don't want to improve their skills and get with the changes in cars, they can go ahead and get out of the business." These are the people working on your cars at the dealer.
When my Explorer started flipping out on hot days a few months after I bought it (it would run and drive, but it would throw every code in the book for no reason), the dealer at first couldn't find anything wrong even after showing them pictures of every error that came up on the display. Finally one day it did it and I drove it in to the dealer screaming and dinging the whole time. They hooked up to it and found no communication between the BCM and the rest of the modules. I instantly said "it's the BCM or something on the CAN bus." After days and many phone calls between the dealer and Ford Engineering, the Ford Engineer told them to check the CAN bus pin in the connector at the BCM and sure enough, the pin was bent. They replaced the pin and it fixed it.
Any mechanic worth his weight, whether he knows computers or not, through basic troubleshooting techniques could figure out "If the BCM can't communicate with the rest of the car, run a BCM diagnostic. If the BCM passes, check the wiring." They should not have had to get Ford Engineering involved. Don't get me wrong, I love my dealer, but their service department is just like every other service department experience I have ever had. A bunch of "factory trained techs" that don't know squat and couldn't troubleshoot their way out of a box without some kind of paint by numbers manual.
I had pulley noise on the Explorer as well and showed it to the service guy when I pulled in. Mysteriously, 2 days later they called and said they couldn't find a problem. Sure enough, I got there and there was no noise. I would have laid money on them just putting belt dressing on it and "not finding a problem." After a few thousand miles, the noise is back. Yup, belt dressing. I'm going to change the tensioner and the belt and take it to them and show them that "there was nothing wrong." It's quite embarrassing driving a 1 year old Explorer with the belt noise of a 1995 Maxima.
But they know better than we do...