OK
here's the deal
I couldnt find a distributor for the 12 way male plug that is needed to make the wire harness. however, this 12 way plug is the EXACT plug that is used in the 03-06 gm full size trucks for their secondary audio plug (also, i think it's in the same place on the 04+ gp's but i dont have one to see that) anywhoo, soundgate makes a $20 adapter that has the male plug we need, plus one of the female ends, it's put together for adding a cell phone, but we're gonna hack it up! (we will just leave the wires/connectors in the male end and butt splice or solder, and replace the pins/connectors in the female end)
need the following:
soundgate GMCELL (or GMCELLV2, have to look on ebay) somewhere $20-$30
one of the following:
12064799 (second female connector)
12064823 (connector pin retainer)
12064822 (connector pin retainer 2)
---cost for these is $1.98
need 14 of these, more if you need spares12089649 (female terminals)
---cost for these is $2.24
--terminals and other plug are sourced from mouser electronics (mouser.com)
after adding this up, figuring 25 for the harness to cut up, and about 4.25 for the other parts, and maybe 5-7 for shipping? should put the mod under 40 bucks (assuming you may have the wire you need to put it together)
if you did end up doing it the harder way, using the header mount, you'd likely cut out almost 25 bucks. so it'd be down in the $15 dollar range, just a bit more work.
let me know if you want those part numbers
