INSTALL TIPS
This best done by a professional but here are a few tips for those who have the skills needed to get the job done. To install a Head Unit(HU) you must be able to solder, a digital multi-meter(DMM), and be confident enough to remove the dashboard panels. A lot of people think you just slip out the factory HU and slide in the new one. If only it was that simple. To remove a factory HU often requires the removal of several panels and can include the centre console panels and even the centre console being moved back. This is probably the trickiest part as often its not intuitive how the panels are removed. Some are simple clipped in and otheres require a combination of panles to be removed in a specific sequence. If you are unsure it is worth jumping online and finding a dedicated forum of owners of your vehicle, as members there can offer guidance.
Assuming you have managed to remove the factory HU, the next thing to do is to determine which leads in the factory wiring harness are what. You will need to find which leads are 12V positive batt(this lead always has power to it and is used to make sure radio staion presets and other settings are retained when ignition is off). The lead that has 12V positive when the ignition is turned on (or key is in acc posistion). This lead turns off system when you turn car off, and prevents you forgetting and then flattening your battery. Some HUs also have an illumination lead. This will trun on the HUs backlighting when your lights are activated. You also need to find the electric/power antenna(aerial) lead if your car is fitted with one.
To find the permenant power lead(which always has pos 12V) you must have the key removed from the ignition. You then attach the negative(black) lead of your DMM to a good earth/ground. I have found the ignition barrel is always a good point. You then probe the pins on the factory HU plug until you see 12Vish on the display. This is your permanent power lead. Next place the key in the ignition and turn to acc posistion. Now probe again until you see 12V positive on DMM. With probe still touching pin turn key to off posistion and DMM should show 0V. You now have your switched power lead.
The next thing is to determine if your fatcory plug has an illumination wire. Some don't and if thats the case you will need to find something that has it(like the dash) or attach the illumination wire to ignition switched lead. To find this lead you need to probe the plug again with your park lights turned on. When you see 12V on DMM display, you need to switch off lights to confirm that its is right lead and DMM should display 0V.