1989 toyota supra

im currently hooking up a JVC deck to my friends 1989 supra. i checked out the wiring diagram under the 12 volt archive and followed both that and the wiring instructions that came with the deck. now, everything is wired up but there's 4 wires that aren't connected.....antenna trigger(no power antenna), illumunation,  a mystery WHITE/ green wire ( not shown in the 12volt wiring diagram) and another wire i assume is for the dimmer. the deck won't power up at all....and there is power from the constant 12v.....any ideas?

Check to make sure the deck is also properly connected to the switched +12 volt wire ("accessory"), and that there is voltage going through this wire when the key is in the "acc" and "on" position.  If you get no voltage, then I'd say check the fuses throughout the vehicle--I'd recommend using the continuity function of a multimeter to verify if a fuse is good, cuz many times even if it looks okay it can still be blown.  You should check all the fuses even if they don't say "radio" on them cuz a lot of times they are mislabeled, and besides wouldn't you want to know if you had a blown fuse in your car?   And while you're at it check the fuse that's in the back of the radio

The three connections that are absolutely necessary for the deck to just power on, are switched and constant +12 volts, and a good ground.  An easy way to check for a good ground is to temporarily run a wire from the constant 12 volts to the switched 12 volt wire in the back of the JVC, because you already know the constant wire is good.  The radio should DEFINITELY power on, and if it doesn't you know you need to find a good ground, or the radio is messed up (very unlikely).

This WHITE/ green wire you're talking about...is that a wire that's part of the JVC's harness? or is it part of the vehicle's wiring?

The fuse has been replaced and there hasn't been any change. The White and Green wire is part of the OEM harness. All of the wires used in the JVC harness have been used except for the Antenna wire.

i know what you're talking about but that's not it.....im not talking about the harness itself.....im talking about antenna plugs...i have to of them, one smaller than the other...sorry for the general statement.