have a avic-n1 that has been working great up till a couple months ago.now i have nothing coming from the speed senor pulse.it reads 0 and no mph.1st time i notice this i did get a error saying eratic speed senor or somthing like that.but now its nothing.i checked the vss wire going to the brain box and im getting power to there.plus i noticed the compass part isnt right.is there someting wrong with my brain box??everything else works fine.

thanks

Check your connection to the VSS wire, first. And, it should read an increasing voltage in AC, not DC. GM vehicles in that era generally used a dark green with a white stripe for VSS. Also, check your GPS antenna, make sure it hasn't fallen off of it's reflector plate or is sitting upside-down under the ashtray....