vss for 1999 mazda millenia

hi all, where do I find the VSS wire on a 99 mazda millenia 2.5? is it under the hood or dash and what color am I looking for? I'm about ready to install a pioneer avic-d1 and don't have a wiring diagram. Someone told me to look under the front left wheel well, but don't know wire color. any help would be appreciated.stereo man

thanks a lot, I also have a bose HU and want to keep the bose speakers and amps, can I just add an interface to ramp down the load going to the bose amps? Crutchfield told me that the bose amps will handle the 4 ohm load from the new pioneer HU and it will work OK that way, but I'm a little skeptical. They just wanted to sell me a factory wiring harness adapter and said it would work fine.stereo man