Truck Repair: cab component indicator, volvo truck, grab rail

Question
Hi, I have a 2003 Volvo truck.  I have a light come on that says CAB COMPONENT.  I have been looking for this part on the internet.  I don't know what the problem is.  Can you tell me if this is something the dealer must work on.

Answer
have you noticed anything not working? and is there a code number that goes with it. the 03 i believe has the little diagnostic box on the left side by the grab rail. if you go into the diagnostics portion of that might give you a little more info on what component is a problem.