Resister
#2
The resistor do the same job with extended harness as it do if you have the stock harness.It works with the pmd and gives the engine the right fuel mix,and that is important if you care about the millage for example, in most cases the truck runs really bad without the resistor. There's a number on the resistor (1-9) and it might be 4 or 5 in stock models if i remember right.
#3