03 sierra 4.3 to 5.3 swap(i need help)

[sonnychills]

need some help!!!!!!!

only one plug im having trouble with, this one...
its a blue/white plug that doesnt fit... motor and harness are from 99-02 and my truck is 03, i wanted to keep cable trottle body. but these plugs do not fit nor have the same wire in the correct spot... also the truck side of the harness has 8 wires and the motor harness has 7, the only wire different is on the truck side which is a brown/black.









this is in big_countrys 04 silvy z71 notice both plugs are white....



DO I HAVE THE WRONG HARNESS?

[00_Silverado_Z71]

I'm going to tell you this now i'm in the process of doing a v6 - v8 swap in my 04 and its damn near impossible to try and make a 99-02 harness fit an 03+ truck and its more trouble than its worth to try and keep the cable driven throttle body. I tried and tried everything I could possibly think of to make this work and it just isn't worth it. Get yourself a harness from an 03+ truck and the drive by wire stuff and save yourself the headache trust me. The pin outs for the 99-02 harness are different from the 03+ so they do not work when you plug in the 99-02 pcm my truck did all kinds of weird stuff because nothing is pinned right in the wiring harness compared to the 03+ in the truck already.

[sonnychills]

I get that but this plug is the only issue I've had. The colors combo between both are the same just in different pin locations, maybe I can just hardener them together and see what happens

[Botlfed]

You can try repinning it, me and a buddy did an 04 standard, converted from a wt edition to ls, we ended having to switch all kinds of stuff, finally after much debate, time, and money we switched to a dbw tb, btw the 04 is the worst year to do.

[sonnychills]

I'm gonna try to call Nelson performance today but I'm thinking I am just gonna re pin it. Everything else plugged in fine except this one.

[00_Silverado_Z71]

You can try repinning it, me and a buddy did an 04 standard, converted from a wt edition to ls, we ended having to switch all kinds of stuff, finally after much debate, time, and money we switched to a dbw tb, btw the 04 is the worst year to do.

I can agree this is what I am doing is a 2004 Standard WT to an LS and after going through every possible option I finally just broke down and bout the DBW stuff. I had went over everything with Allen at Nelson also and all decided the best and easiest option was to do the dbw because he didnt even have a vin to program a 03+ for dbc. Which pcm are you trying to run the 03 or the 99-02 style?

[sonnychills]

99-02 style with cable ecu has already been tuned.

[00_Silverado_Z71]

Ah ok good luck. I tried the same and never could get it to work have you repinned the harness at the pcm? The wires are different as everything uses different pins at the pcm and at the fuse block for the 03+ as I found I had already gotten mine tuned from nelson as well and ended up just having them swap it out for an 03+ pcm dbw. When I initially tried to do this same thing with my truck I turned the key on and about 90% of things in my truck did not work as far as gauges, controls, lights, etc.... went to start my truck I pushed the clutch in and it started cranking trying to start itself without even fully turning the key. Thus why I just got rid of the headache and changed to dbw and a 03+ harness

[sonnychills]

Haven't tried to repin yet but will today, all the wires are the same color just not in the correct pin. Guess I'll just have to try and see what happens. And this plug comes from the motor harness and connects to the chassis harness that gies down the frame rail. It doesn't go directly to the ecu or into the fuse box!

[banker099]

03 express vans had dbc and return style fuel system still