I need a new wiring harness for my 03 six speed HO. First of all, where is the buest place to get one? And second: It has a built engine that went in a few months ago so I dont really have an engine serial number. I know there are at lest two variations of the engine in 03 which would have different wiring harnesess so im afraid of getting the wrong one. My truck has the throttle position sensor mounted underneath the driverside battery as opposed to the second gen style TPS on the block like I have seen on some 3rd Gens. ALso my ECU has two identical multi-pin connections side by side at the top. Im not sure what the other style ECU is for the 03s but I know there are two.

Does anyone have any suggestions as to how to determine which harness I need??

 

I would try to find someone that is parting out a truck and take it off yourself. You probably also need a harness from a 6spd vs an auto tranny. You could probably use one with either TPS setup provided you got the TPS and cables to go with it.

Why are you replacing the harness?

I have one from a 2004 auto sitting in my garage but not sure which TPS setup it has.