hey guys, i have a 1991 z28 with a 305 auto 700r4 and the speedometer doesn't work everything else works odometer, trip, oil pressure ect...i tried unplugging the vss to see if the SES would come on and it didn't so i thought ok i'll try unplugging something else so i did and the SES didn't come on again, the thing is the car runs fine so i know it's not a faulty computer, im just wondering if you guys could help me out with these two qestions....

 

does the speedometer have a ground wire and if so where is it located?