Depends on the unit, the instruction manual should tell you. Most aftermarket NAV units are looking for an 8-pulse signal. Others allow you to specify it in the setup. Some (like my Eclipse AVN5500) have the ability to "learn" by counting the speed pulses and comparing it to the GPS data. When I hooked mine up to the 8-pulse I had to simply drive around the block and the unit learned it.So which one should be used for aftermarket navigation? I just ordered the Pioneer Avic-D3
It's worked fine on my D2. It's been hooked up since Christmas.I have the AVIC D3 and just hooked up the speed sensor wire to the white with gray wire in the AC unit as described above. I will let you know once I power it up to see if it works correctly on the D3.