I need a radio wiring diagram for a Holden Commodore LS 1991

Regardless of colour coding, please follow the following instructions (require multimeter):


Note: Attach multimeter earth wire (black) to the vehicle body. Convenient places may be the metal ignition barrel, the vehicle's car arial plug, cigarette socket body etc.


1) Testing for voltage with key out of the ignition, locate the permanent positive wire. This will wire into the yellow wire on your new stereo. The yellow wire circuit powers the stereo's memory.


2) Testing for voltage again. This time you are testing for a wire which only offers power with the ignition turned on. This one will wire into the red wire on your new stereo, and will power the unit only with the ignition on.


3) Now you know which your vehicle's positive wires are you can now test for an earth wire. Switch the multimeter to the resistance setting. There is one setting which will allow a buzzer to sound once you find continuity. With the ignition off test each wire until you get a buzz and a low resistance reading. This should be your earth wire. Double check this with the ignition in the on position. It should remain the same. If it changes to a positive with the ignition on and with the vehicle's lights switched on, then this is the dimmer feed for the stereo's screen. If you unintentionally found the dimmer feed, then you can ignore this wire, and search again for a wire which only offers an earth.


Now you have your power and earth wires located and can wire these into your stereo before continuing.


4) Next you need to use the stereo's balance and fade controls to allow only one speaker output to work from the stereo. So let's start with Left Front speaker output only. turn the stereo volume to mid way so that you can hear when you have connected to the right speaker. bare the remaining wires on the car side and test combinations of the remaining wires until you find the front left speaker of the car. Wire your stereo's wires once you find the correct connections.


5) Repeat the above steps with all remaining wires, remembering to adjust your stereo's balance and fade controls to only allow one speaker output at a time, to ensure the only one possible channel to work and help you identify which of the car's wires power the speaker you have selected.


Before re-assembly of the dash panel, check that your stereo and all functions work properly, being sure to use your fade and balance controls again to test all speakers individually.


If you want to be extra careful and wire the vehicle's speakers positive and negative, according to your stereo's outputs, not that this makes much difference on standard stereo arrangements, then follow this next step:


Make sure you can see the speakers themselves and connect a 1.5 volt AA or AAA battery to the speaker wires. If the speaker's cone pushes forwards, then the wire you connected to the battery's + terminal is indeed the positive wire and should be wired as such. If the speaker does the reverse, then you have the wires the wrong way around. Do not repeat this test for extended periods as damage may be caused to the speaker circuit.


Tip: Always solder all connections and insulate well from each other. Stereo connections can corrode over time and are prone to movement behind the dash. Poor connections may cause faults and low quality sound.