My speedometer needle use to jump around and when it did my cruise control would shut off on the car. It would return to normal and the cruise would again work. The speedo finally just quit and now it, the cruise and my odometer and trip odometer don't work. I replaced the VSS and it still doesn't work. What is wrong?

 

Check to make sure it is still grounded. If the speedo slowly started to jump around, it's ground connection may have been slowly coming loose and now it just completely lost it. I'm not sure where the ground wire is for the speedo though. Follow the wires coming out of the VSS and you'll probably find it. It could also be grounded near the ECM so check into it.

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1991 Z28 - 350 TPI, T56, McLeod street clutch, LT4 pressure plate, Pro 5.0 shifter, ported plenum & runners, AFPR, Holley Annihilator ignition box and wires, Hooker shorty headers w/o AIR, Flowmaster muffler, homeade ram-air, SSM subframe connectors, Kenny Brown STB, Global West steering box brace, Steve Spohn adjustable torque arm and T56 crossmember