Don't give up, there is a solution. I had the same issue with my 74 B200, but I found how to fix it. The problem at the moment is I can not for the life of me remember how I did it. All I seem to remember at the moment is I purchased another unit from a different vehicle and managed to make one working unit from the two pieces. I have not had any issues with it since I have fixed it. I will post another reply if I can remember how I did it.