Okay. Important Update
I got pulled over for the first time with under glow. The officer told me he WAS going to write me a ticket. On the way to his car, he stopped came back and asked if I could turn the lights off. I responded asking him if he could double check the statute on auxiliary lamps for the State of Wisconsin. It helped that I had the print out the statute where he could look up the number and not spend time on it. Because I asked him (will extreme politeness because face it, i'm 20 and I have under glow.. not the best combination) he came back and said *quote* "I'm actually sorry for the inconvience but you are absolutely correct. Having
White in front, amber on the side and red in the back is absolutely within your citizen rights." What I have is Wisconsin law statues. I also am posting below Illinois and Indiana. If you need help let me know and I'll try to find your states laws. =] enjoy driving legal. For help, email me at jmoddes@gmail.com and give me up to a day to respond please.
https://legis.wisconsin.gov/Statutes/Stat0347.pdf Wisconsin Law: #347.05 (2)
https://www.ilga.gov/legislation/ilcs/ilcs4.asp?DocName=062500050HCh%2E+12&Actid=1815&ChapAct= 625%A0ILCS%A05%2F&ChapterID=49&ChapterName= VEHICLES&SectionID=28705&SeqStart=120700000&SeqEnd=131800000&ActName= Illinois+Vehicle+Code%2E Illinois Law: Chapter 12, Article 2; Sec. 12‑207 (a) (b) & (c)
https://www.in.gov/legislative/ic/code/title9/ar19/ch6.html Indiana Law: IC 9-19-6-8
Three states all saying
White or Amber in front
Amber on sides
Red in Rear
-Jordan

that's pretty much comman in most places......however what you need to know is the number of lights that are allowed, usual 4 front white lights.........
For us, as long as the under car light is not directly visible from side, front or rear your fine regardless of colour, there aren't any regs on lighting facing down.