My harness had different colors so maybe we can get it right by function. Looking at the four lug socket on the motorhome the upper left is the left turn/brake, lower left is ground, upper right is right turn/brake and lower right is taillights.
Sorry Matt but Steve is on the money. You will have to use your VOM to figure out which is which. Those are non standard colors for tail light wiring
Richard Rhonda Ty and Alex Entrekin
1995 Newell # 390 DD Series 60, Allison World Trans
Subaru Outback toad
Often wrong, but seldom in doubt
Rhonda's chronicle https://wersquared.wordpress.com/