I have an 02 f150 xl, I'm taking the stock head unit out and replacing it with a Pioneer 1900. I didn't buy a connecter I'm just splicing the wires together, I know I shouldnt do it that way but it's to late now, what my problem is, there are three ground wires coming from the truck and the new head unit only has one ground, I just looked wiring diagrams up for both head units and that got pretty much everything done, just there are two speaker ground wires that are black and green, and then a regular black ground wire, I'm not sure if I should connect them all together or cap them separately, because I connected everything up and the head unit wouldn't turn on, so any thoughts or advice would be greatful

 

Your not going to want to hear this but my advise is never cut the factory harness and this is the reason why.

Well, too late for that so, no you wouldn't cap all the negatives together as the speaker negatives are not chassis grounds. Do you have access to a multimeter? If not, go pick one up for $15 (bout the cost of the harness that you should have bought....sorry). You need to establish 3 critical feeds #1 Chassis ground, #2 12v + ACCY (on with ignition only) and #3 constant 12v+. From there the rest will be easy.

 

I got the head I it all hooked up and working although I appreciate the response, I tried hooking my subs up and for some reason the amo isn't receiving power even though its all connected with the fuse and everything not reall sure why