i have a 87 firebird 350 with a 700 r4 trans in it. the speedometer is electronic and i traced the wires to that yellow box right by the computer on the passenger side, and the little plug going out of the yellow box that has the purple and yellow wires go straight to the trans, or does it go somewhere else? because i cut in those wires and hooked it up and my speedometer dont work but the trip meter works. i just drove it down the road a 1/4 mile and it says i went 7 miles. but the needle didt move at all. please help i dont want to buy a new speedometer cause they like $200. and i like the one thats in it.

 

please help me