I have a 2003 single cab with a v6 I want to put my 2002 5.3 in it could some one tell me weather I need to keep the fuse box and get a 2003 v8 harness and just pin out the drive by wire and make it cable or do I need the 99-02 harness with the drive my cable and the fuse box ?

 

fuse box is the same, you can use a v8 DBW harness or DBC just need the ECU programed for the throttle body your using, ECU's are the same also just needed to be programed for the engine your installing

if that was your question?

 

Fuse block is the same. You can't use a 99-02 harness. If your 03 v6 is drive by cable you have a three choices with the correct V8 03+ engine harness. (1) add IAC and TPS to the harness and run drive by cable & throttle body. (2) Find a harness and PCM from a 03+ Express or Savana van and run drive by cable. (3) Replace cable accelerator pedal with a drive by wire pedal and TAC module and run a DBW throttle body.

If you decide on a DBC system the PCM must have the IAC (idle air control chip). Some P-59 PCM's do, some don't. You can use the tried & true P01 (0411) PCM but you'll need to swap the plastic green harness connectors for the red connectors as the P59 and P01 are keyed different. The P01 will limit things like E85 and also 3 bar support if you're doing forced induction... without an OS swap.