[old_master]

Stop and turn signal use the same filaments in the bulb. The signal has to be split or both left and right rear turn signals would come on when you hit the brakes. Old design and still done that way. The only way around it is to use separate bulbs for stop and turn, which some cars do.

The hazard switch can be serviced separately and is not a difficult job at all. If you look in the Blazer "How To" section, there is a thread that shows how to do it.