Radiator fan help..electrical aspect

[not a gt]

Hey guys, I have tossed this around in other threads , so giving it a home! Long story short, brought car to dealer with no high speed, but had low (low on at 172-174, high speed on at 181). Dealer changed CCRM, got home and put in new radiator (fan was new). Now I have high speed but no low (and fan comes on with A/C). I went ahead as well and changed reistor on the fan. Under the hood on passenger side front by air cleaner is a one fuse (30A) box that I found is for the fan. I checked and no power there with key on, upon starting and no power at fuse when I hit low fan temp setting in my tune. Anyone knew exactly when this fuse gets power? As well from a wiring perspective, is there another fuse somewhere supplying power to this 30 A single fuse? As well, can't find info on where power enters this fuse holder and where it goes out to. Any help would be great...also I did a Exhaust gas test in coolant and results were negative and I have no coolant in oil ( car tends to run hot driving..water pump about 2 years old..a stocker, and 170 Stant T stat with hole drilled less than a year old)..thanks again for any help fellow Mach 1 enthusiasts