where is the speed detection circuit

[lurch20420]

i am trying to install this pioneer nav system and it requires me to tie into the speed detection circuit lead and im at a loss as to where and how to do that and also where was a good place for the hideaway unit to be placed

 

[hyde]

What is the purpose of the speed detection? GPS detects that based on the unit not the vehicle's odometer or movement. Does it have something to do with DVD playback?

 

[JLRockies]

Vernal....

 

[lurch20420]

the speed detection circuit lead is for the system to track the distance and speed traveled its on the main harrness somewhere but thats a needle in a haystack to me