2003 Ford Explorer head unit

Just to show how green I am at this stuff, I just received my new head unit today and I am hooking up the wires in my harness with the harness adapter I got along with the HU for my Explorer. The harness that came with the HU has a ground wire with receptacle for connecting to the vehicle chassis. The factory radio had no such connection. I'm assuming I do, but do I have to connect this to the vehicle? Nothing I have read has said to do with this with a HU. Probably a dumb question, but you know :-).....thanks2004 BMW 325ci.

Alpine CDA-9885

JL 300/4 and 250/1

JL XR 5.25 comps

Infinity Kappa Perfect 12

Yes you have to hook up the ground.  The factory HU has a ground connection but your not going to see it.  Just connect it and you will be fine.1999 Chevy Lumina

Pioneer Deh-p6400 HU

2- Pioneer TS-W304C

2- Pioneer GM-X972 Amps

2- Pioneer GM-X572 Amps

All Pioneer speakers

4- Lightning audio 1 farad Digital Caps

And All Done By Myself

Ok thanks.....there must be a bolt or something in there I guess....2004 BMW 325ci.

Alpine CDA-9885

JL 300/4 and 250/1

JL XR 5.25 comps

Infinity Kappa Perfect 12

ok, one more question then...the adapter harness I have has a wire for chassis ground...and the stereo harness has the wire with the clip on the end for connecting to ground. What does the chassis ground wire from the harness adapter go to?2004 BMW 325ci.

Alpine CDA-9885

JL 300/4 and 250/1

JL XR 5.25 comps

Infinity Kappa Perfect 12

duh, I guess the ground coming from the adapter harness wouldn't be used. The unit would be grounded from the attachment coming from the HU harness...2004 BMW 325ci.

Alpine CDA-9885

JL 300/4 and 250/1

JL XR 5.25 comps

Infinity Kappa Perfect 12

Just attach the black wire from the deck to the black wire on th adapter harness. If this means cutting the end off the deck ground then chop that bitch.double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer