So I just purchased my new Pioneer AVIC F900BT today and should have it soon. I was reading the installation manual and it says that I have to wire into the CAR SPEED SIGNAL INPUT. Does anyone know where I can locate this and how to safely tap into this without screwing up the wiring. I have never dealt with audio equipment, but I am going to have my cousin help me out who has worked with it a little. Any advice would be very helpful.