If your existing fan rotates counter clockwise you need a reverse rotation fan. The general rule is if your vehicle has a "V" belt it is standard rotation. If your vehicle has a serpentine belt it is counter clock wise or reverse.
You could use the Derale 18" Rigid, Steel-Blade Race Fan - Belt Driven part # D17418 to replace your current fan. It is the diameter of the fan and the RPM, not so much the depth that would make the difference. However, I recommend to add an electric radiator... view full answer...
The Derale Radiator Fan part # D17319 is standard rotation. If you need reverse rotation the part # D17419 is same fan but opposite direction. view full answer...
Sounds like the problem is the ground wire of your brake assemblies. If you have power to the assemblies but the ground wire isn't connected to a clean metal surface of the trailer frame then you would have the problems you described.
Also check the condition of the main trailer ground that goes from the trailer connector to the frame of the trailer. view full answer...
The two MagnaFlow crossmember-back exhaust systems you referenced, parts # MF15893 and # MF15897, differ primarily in their cost and pipe diameter, as you noted. Both systems are 100-percent stainless-steel exhaust kits that include all hardware, straight-through mufflers and a true X crossover to balance airflow for improved power.
I would stick with the 2-1/2-inch diameter kit # MF15893 unless you have the 4 barrel carb and are using a high-performance air filter. Air intake and exhaust... view full answer...