exotics wiring colors

I'm installing GPS with starter kill and door locks on a Lamborgini Murcielago, Maserati Quattroporte, Mercedes CLS, and SL. I use directtechs and they have nothing listed. I called tech and they had nothing for me. I also checked Audiovox tech but nothing. All I need is the starter and lock wires for the above cars. The customer wants me to do the cars onsite so I want to have my ducks in a row before starting. I've worked on a Lamborgini Gallardo before and it was simple. I'm guessing the Murcielago will be easy. The benz with the laser key, and Quattroporte are the ones that have me worried. I know I can find the start wires on these vehicles. I just don't want to throw any lights on the dash by doing so. Thanks for any help.

I'm in NC. Who is Howie?

I sent Howie II a PM. Thanks.

The locks on the Maser and Lambo will be the same, low current neg, either find the lock control, probably a blue relay or go to drivers door loom(good luck with the Lambo). Did a Miura recently and I had to pull the inst. panel to get at the ign loom since the steering  cowling retaining screws had rusted themselves in! You will have to check the ign wires to find the starter. Starter should be a purple base colour, ign pink/red on Mercedes.  DIODE the ignition feed to your unit as feedback will cost you lots of £ (or$). Pick up the starter and ignition from the main (larger) engine bay fuse box  since the ign key is data. If you can check the audiovox data they list these Mercs  up to 2007 and list lock/unlock. Directed are a waste of time, all they want to do is sell their CAN alarms, so they just list the CAN wires. NB. I'll be doing an alarm and tracking on an '08 S class in the next couple of days so it might be interesting.

Thanks Howie. On the IGN feedback. Do I need to isolate 12v as well? Should I catch it at the Batt. instead of the IGN harness to avoid this problem and maybe use a relay activated by ING for IGN to avoid feedback or will a diode be enough? I have worked on a Gallardo before and it was simple. Did a Diablo back in the day and it beat my ass. Many thanks Howie.

 First ONLY go to direct battery or main non-shutdown fusebox feed, otherwise warning light issues etc. It's the recovery time getting my back to work again after doing a Lambo that gets to me every time. I had a thought, I do a lot of tracking installs and on larger vehicles and I nearly always go to the rear because you can place the antennas in the (plastic) light housing or inside the (plastic) bumper.  Usually in these larger vehicles you have battery at rear and usually an ign circuit. In the Mercedes case you  might have a fuel pump relay in the vicinity, see where this is going? N.B. A friend's company were doing track + starter kill on a Mercedes truck, didn't diode the kill relay feed back to the CPU guess the rest. So DIODE before relay!  For the best relay coil shutdown explanation I've ever seen see this websight, "powering a trunk solenoid" the post by "I am an Idiot"