2001 Monte Carlo BCM problem

I've brought my car to the dealership twice now to have the keyless entry system reprogrammed. My problem is that the system automatically switches to the horn audible when locking and unlocking the car. I prefer that only the lights will flash. I told the dealership I would settle for not audible or flashing of the lights. They said it may be a BCM problem, but to leave things alone for now due to the cost of repair. My feeling is that they're just guessing and not really sure what's going on. Does this sound like I need to replace the BCM? If so, any idea on cost? What to ask when finding the right place to do the job? Any assistance is appreciated. Thank You... Mac