94 GMC suburban wiring

Somebody help before I pull my hair out!!  I took out the stereo that the previous owner had in there.  He didn't have an amplifier so he had all the speaker leads from the h/u wired into the harness which connected to the factory harness and the stereo worked fine.  After I removed the stereo and put in a panasonic h/u, my dome light doesn't work, the stereo doesn't work and my door locks used to unlock when the key was removed and they locked when the key was turned...but now those don't work either...they will still lock but I have to use the remote to lock and unlock.

I connected the panasonic this way:  red from h/u to red on harness  /  yellow from h/u to yellow on harness  /  black on h/u to black on harness / and I didn't use any speaker wiring from h/u because I'm using rca's for amps to front and subs.  I should have paid better attention before I disconnected what the previous owner had wired but I didn't...but using a harness to plug into the factory harness it should be as easy as what I did above, right...?

If anyone can help I'd really appreciate it.