Where is the backup light switch on a 1999 Chevy blazer ls with automatic transmission?

The 1999 Chevy Blazer LS (automatic transmission) doesn't have a separate backup light switch in the conventional sense like you might find on some older vehicles. The backup lights are controlled by a backup light switch integrated into the transmission itself. This switch is activated by the transmission's shift linkage when you put the vehicle into reverse.

Therefore, you won't find a separate switch to replace or adjust. If your backup lights aren't working, the problem likely lies within:

* The switch itself (within the transmission): This is the most common culprit. It's usually a wear-and-tear item and requires transmission access to replace.

* Wiring: Check the wiring harness leading from the transmission to the lights for damage, corrosion, or loose connections.

* The backup lights themselves: Make sure the bulbs are functioning and properly seated.

* Fuses: A blown fuse could also cause this issue. Check your owner's manual for the fuse location and rating for the backup lights.

In short, there's no switch to adjust; you'll need to diagnose the problem within the electrical circuit or the transmission's internal switch.