So I installed my trailer plugin. Had a little confusion on the wires but got it half working. My four flat is good but my 7 prong isn't. Does anyone know what the wire setup for a stock 99 full-size 7 prong is?

I got my four flat working for breaks signals and running... No reverse and can't say what works for the 7 round as I don't have a trailer that uses it. So really more worried about getting my reverse woring