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GUIDE : Installing Aftermarket Head unit

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  • GUIDE : Installing Aftermarket Head unit

    If you have any Questions or Comments ask in that thread, I can help.
    - Complete English z20 Wiring Diagrams
    - All Circuits
    - Every Connector
    - Completely in English.

  • #2
    I'm getting invalid thread.
    How do I removed old stock headunit?



    • #3
      First, unscrew your gear knob be it auto or manual then take out the two screws on the either side of the gearstick surround. Next is the two screws facing almost vertical just above the head unit itself. Now you can take off the gear surround, careful when you do this as there might be wiring for switches for stuff like the ECT on the auto or TEMS depending on your car, obviously just unplug the wires. Next you have to sort of slide the aircon panel thingo towards you, only pull it out a couple of cm so it's still resting ok, you don't want to have the weight of it dangling by the wires behind. Now you have to maneuver the gear surround off, this is a little tricky the first time. I put it in L, separate the aircon panel and surround then try to angle it out. You should see which bits are getting stuck. Make sure the gear knob is angled sideways so you can get the surround past it, it doesn't fit through the hole whilst it is facing the normal way.
      After this you'll see the four screws which hold the head unit in place. From there it's really straight forward.

      Circled in red are where the screws are:
      86 mica red GZ20 manual


      • #4
        Sammyboijenkins- Thank you so much for the help. I finally got my steering wheel adapter and installed that with a Nardi steering wheel. After that I had some free time today and got to work taking the stock unit out. Took me about 2 hours to finally get that sucker out.
        Now I gotta figure put which wire is what. Do you or anyone have a wiring diagram for the wires to head unit?


        • #5
          To future readers, I forgot to add; you need to remove the centre console armrest thing before you can get the gear surround off. There's a single screw holding it in that is located in the little storage compartment.

          Getting out the old multi meter will be quicker than waiting around for a diagram. Chop you old loom then go hunting.
          The wire that has 12 volts when the key is off is your constant power. Earth will probably be a black or brown wire and you will see going to a ring terminal connector that connects to the body off the car just under where the stereo sits.
          The accessory switch will be the wire that only gets 12 volts only when the car is on ACC or ON.
          I found which speaker wires were which by having music playing then trying two wires at a time and seeing which speaker the sound comes out of. The two wires for an individual speaker should be close together so try pairs like that instead of trying two random ones from the loom. If you do this method make sure the other exposed wires can't contact anything that they can short out on anything.

          After I did this I had three or so wires that weren't doing anything, obviously you need to make sure they can't short anything. Heatshink, electrical tape etc. is the go here.
          86 mica red GZ20 manual


          • #6
            Ok, I figured out which wire is which.
            The wiring color is confusing. Its not your standard, where yellow or red would likely correspond to constant positive. On mine, it was the Blue/yellow stripe wire that was constant +12. Gray was the switched ignition wire. Brown was ground but there were 2 other wires next to it that was ground as well. One wire was connected to the antenna plug and that was ground.
            I'll take a pic of my wiring loom later tonight.
            Last edited by DaSurfa; 17-06-2014, 04:28 PM.


            • #7
              I finally found the Toyota Radio wire harness diagram.

              Here's a pic of my harness off my '87 Z20.