How do i change reverse lights in an 2003 impala

Remove the light housing (not easy) and inspect the cushion that surrounds the lightbulb holes and replace if needed. You may have to pull off a gray trunk lining to access the nuts for the light housing.

2000-2005 Chevrolet Impala Interior Fuse Check - 2003 ...

www.carcarekiosk.com/video/2003_Chevrolet_Impala_3.../fuse.../check

The video above shows how to check for blown fuses in the interior fuse box of your2003 Chevrolet Impala and where the fuse panel diagram is located.

Replace a Fuse: 2000-2005 Chevrolet Impala - 2003 ...

www.carcarekiosk.com/video/2003_Chevrolet_Impala_3.../fuse.../replac...

The video above shows how to check and change blown fuses in the engine bay of your2003 Chevrolet Impala in addition to where the fuse box diagram is ..

I had the same problem solution got to change the tranny this is the simple way

2003 CHEVROLET IMPALA REPAIR MANUAL

click the link to get your answer

You should check the firing order again. It sounds like you have two of your plug wires reversed.

The battery is under the hood, just behind the passenger headlight.
There is a black bar that crosses over the battery and goes back towards strut tower. Remove this bar and the three bolts; probably a 12 or 13mm socket.
Remove the negative (black) battery cable with an 8mm socket or wrench. A 5/16" should work also.
Then remove the positive (red) cable with same socket.
Remove the battery clamp and bolt. Probably a 12mm socket with extension.
It's tight, but the battery can be removed.
Reverse instructions for installing the battery. (That includes hooking up the red battery cable first, then the black cable.)

Remove license plate. Unscrew the screws on the underside of the bumper. Slide the lights back toward the trunk and then down through the opening. Unscrew bulb and replace with a new one.

Reverse steps to reinstall the lights.

I suggest changing your egr valve. I have a 03 impala with the same problem and check engine light came on and through the code for the egr valve. they are 154 at autozone

Open the hood & look for two white sliding clips. Pull them up to remove them. The headlight assembly should easily pull out. Identify the wiring harness & unclip it. Reverse the procedure to reinstall