Yes I actually did resolder the board. My Aunt works for Digital and makes motherboards and circuit boards for a living. After resoldering and checking all the diodes the cruise control works PERFECTLY! No intermittent, etc. Note that even with special magnifying glasses you will not see any breaks in the solder. My understanding from my Aunt is that there is not so much breaks in the solder, but the solder itself flexes and "unattaches" from the circuit board and the solder point itself. When you solder a bad solder you will see it "suck" the solder in, as my Aunt describes it.
I also resoldered my climate control unit fixing this, and saving me a couple hundred bucks.
Barrie---where do you buy the IC's? My Aunt said you could not test them since you would need a propietary diagnostic tool connected to the amp. And by the way there are a ton of IC's on these units. She also said the IC's were most likely programmed, so if you replaced you would just be replacing with blank IC's. Tell me if you know anything different.