I suspected as much, I had a C-15 in my 06 Western Star and had the same problems. To answer your question about a web site, no there are none that will give you any specific info on diagnosing and repair of the actuators, Cat keeps very tight tabs on their service info. That being said the best thing you can do is take it to a competent Cat dealer and have them fix it, because there are several different tests that need to be done to detemine which actuator is messed up, whether it is the actual actuator or just the electric solenoid and which specific cylinder or group of cylinders are malfunctioning.
If you run the vehicle throughout the country I used to deal with a shop that can deactivate the things so you won't have any trouble with them again, but they have to be working correctly in the first place. If you are interested pm me and I'll let you have their name and number.
Duane