general problems of the 2002 Buick Rendezvous

Bought my Buick 2002 Rendezvous a year ago with only 45,000 miles on it give or take. It was great until about 6 months into owning it when all of a sudden the lights would flash off driving at night (very unsafe) then when I would go to turn off the vehicle the lights won't shut off at all. . . They would flash and carry on the whole time I was driving. Then the service engine light came on and then the security light. One day the locks started clicking on and off. . . . The radio locked up. . The air conditioning won't work. . . The horn stays on so loud it is deafening and frightening to all cars around you. . . It is so loud you can't hardly stand it. . . It won't shut off. . Went to Buick dealer they said it would cost probably close to 1000 to fix. . . Til they diagnosed it. . . Another garage couldn't even figure out how I was going to shut off the lights. . . I told them to please disconnect the battery cable to at least reset it. . . My son is a mechanic and asked around and found out it is a common problem with this Buick model and year and is the body control module and happens a lot in gm vehicles. This is a very dangerous thing. . Lights going off while driving. . Lights staying on to cause battery to die. . . Horn blowing so loudly. . It is unbelievable. And there is no recall. . This is so wrong. When you research online you see many owners with these same issues. . . To me this is a safety concern and not right that people who may not have the money to fix this are stuck with it and are unsafe. Gm knows that this part is going out a lot in their vehicles and they do not recall it. I feel this is a huge safety concern. . . All of the things that flash in the vehicle on and off are very distracting while you are driving. . Especially having no lights.