I own a 1999 Lighting and the previous owner had replaced the gauge overlay with an aftermarket one. I really want to change this because the speedo on the new one goes to 100MPH (origianal is 140), therefore I can never tell how fast Im going. Also, there is no "boost" gauge on the aftermaket one either. To keep it short, I searched all over trying to find an overlay but could not, so I purchased the whole instrument cluster used on e-bay. I installed it and now the truck wont start (chimes rapidly as soon as the key is put in, and cranks over but only the "theft" light flashes rapidly. I would consider swapping the overlays, but the "boost" needle never moves on the original one, so Im not sure if it is broke (it is plugged in at the back via a vac hose). I already tried to see if reprogramming the key would work, but it did not. Put the old cluster back in, and it works fine. Do I have a bad cluster, or do I need to do something else ( reprogramming)?

 

Yes, any replacement cluster has to be programmed in to work with the anti-theft system.