i have a 2005 chevy duramax i have installed a pioneer avic-d2 navigation system in it and it needs to have a wire hooked to the vehicles speed pulse wire. I thought that it could be hooked to the wire coming out of the transmission but heard that thats not the correct wire. i was also told that the speed pulse wire comes from the "PCM" i have no idea where the pcm is. I found a box that is hooked to the fan shroud but it doesnt say pcm it is labeled by allison transmission though, i also found the box next to that one, that is mounted below the battery box (driver side). I have no idea where to look or what color the wire might be. Please help:D

ThumpersK_A@yahoo.com

Should be in the big loom of wire comming out of the fuse box under the hood...iirc correctly it is a green wire with a whits stripe...best bet is to have someone help you locate it...the way i did it just to be sure i was tapping into the right wire was to sit on the fender while my buddy drove ahead a few feet at a time as i out a test light on each of the wires (there are a few different wires that are green with a white stripe)

I would wait and confirm what i said before trying it...its been awhilw since i did it and i am sure there is a good chance gm has changed wire colors..i did it on my 01' gasser

Try these places.
Smaller radio plug, dark green wire on pin E
Instrument panel plug, green wire w/white stripe on pin A4
Relay center (upper left of brake pedal) top row middle plug, dark green wire pin D

Thank you for your help the green/white behind instrument panel a-4 worked. I appreciate all your help