Completely understand. The fans were a premium at one time from the yards... I have a set rom an 05 Yukon I paid $250 for like a sucker. Rock auto sells brand new Dorman fans for like $130 which is what I have in my truck and it's a long story why I have 2 sets, but the short is do yourself a favor and use the factory wiring harness. I have the expensive factory ones in a box I need to get rid of, but due to size would be better to sell locally at a big loss lol.
Check the manifolds for broken bolts as we have all had them break and is a known problem. The tune would be a good start with basic maintenance.
Sent from my SAMSUNG-SM-T377A using Tapatalk