Try this first, pop the 4 way flasher switch in and out a couple times, do they work? Then try the brake lights again. Because of the design of the 4 way switch they have a lot of load on them and the internal parts like to melt. Then you end up with odd lighting issues. Loss of brake lights is one of the most common. The 97 Blazer should have the same switch as the later S series used and GM makes a kit (15174447 or 15177379) that replaces the switch stalk very easily (they just pull out while the 4 ways are on) but don't pull it out just to look, if it is melted it won't go back in correctly and now you lose signals and more. The one I'm referring to is shown below. They were red or black depending on the exact year and GM "make" but they all used the same insert.
See if anything changes and let us know please.
Oct 8, 2025 at 6:16 PM
