GMT800 Cab Swap: 2002 → 2003 1500 Ext Cab, Rust Control & Questions

[SilveradoPhil]

Starting a thread about moving the complete 2003 dash and HVAC/heater system into a rust‑free 2002 GMT800 cab. I'm swapping everything over — dash, harness, HVAC box, blower, and controls — and want to know what differences to expect between the 02 and 03 setups, wiring, and mounting points. Any advice from people who've done this swap is appreciated. More questions forthcoming. Thank You

 

[stutaeng]

I've never done a complete wiring swap, just know some of the basic differences between the 99-02 vs 03+.

I recommend you download all of the wiring diagrams from AllData or something similar. Study the diagrams and find any differences. Maybe create a list to check off as you are swapping away.

Good luck and interested in any updates.