1999 suburban

Hey everyone. Another newbie here to the forum. I bought my '99 new from the dealer and have done all of the maintenance and some heavier work on it over the years. Now there's a mystery. I put a little gas in and forgot to close the cap. A few miles later it died and the only codes I have...

Hi, When I shift into reverse, the corresponding lights do not turn on. Thinking maybe they were burned out, I replaced them but still no dice. I checked the driver side dashboard fuse panel as well, all fuses are fine. Turn signals, brake lights, etc all work fine...it's just the backup...

Does anyone know of nerf boards that fit the 99 Suburban 3/4 ton 4x4??? I have seen some for the 2 wheel drive, but not 4 wheel drive. Any help is greatly appreciated...