Reverse Lights Not Working

[513Tahoe]

Hi everyone, I have a 2012 Tahoe PPV with about 153k miles. Everything works fine on it except the reverse lights. I've checked the bulbs, and they look fine versus a burnt bulb. When I am in reverse the bulbs don't turn on and it's just the red lights. The only other things I have questions about are the auxiliary battery and a random switch that I found in the back that I don't know what it does. We have a 2011 Tahoe PPV and our mechanic had to take the aux battery out and the terminals because the vibration of the vehicle caused the metal to be exposed and it blew a couple of fuses. How easy is it to remove the terminals and is there any downsides to losing the auxiliary battery if I don't use it for anything?
I'll attach a photo of the random switch that I found.

I don't have any photos of the vehicle but I will post the link to the auction when I got it. https://www.govdeals.com/asset/8915/10337

 

[Joseph Garcia]

An auxiliary battery is not necessary, unless you have some external components that need power.

I'd pull the backup light bulbs out and check the inside of the connectors for corrosion. If they look good, get a volt meter and see if you are getting 12 volts at the connectors, when the truck is in reverse.

 

[513Tahoe]

When I get the chance I will try using a voltmeter to test the voltage coming through. How hard is it to disconnect the auxiliary battery terminals? Is it as simple as removing some bolts?