1999 Pontiac Sunfire dash lights on

Had same exact problem with 97 sunfire, fixed easily, was ground wire to body. (Neg batt cable grounds right to batt box or platform or what ever you want to call it) mine was broke off. Its a flat piece of copper mabey. Has hole in it and bolt goes through it right into the batt box. I ran a wire from negative terminal to this bolt( since mine was broke off) fixed immediately. Disconnected it to test, problem returned, hooked it back up and problem was solved. Ill bet its body ground!

I had the same issue that StaceyLee stated earlier. I put a new ground wire next to the battery, because it became corroded off. About 600 miles later had another ground wire come lose. I could not find it. Took it to the shop and they had replaced it. About 5 days later my cruise control no longer worked. Soon after that my air bag light came on. My headlights are having issues. Issues being that when I turn the headlights on they are on until I hit a bump they shut off completely. My instrument panel does the same as the headlights. They work and will sometimes stop working. If I smack the dash they begin working again. I feel like this a a ground wire issue but have no idea where to look the ground that connects to either the engine or I was possibly thinking to the PCM. I know the basics about car care, which is why I found the first bad ground. I think the shop repaired the ground to the engine, but it may have easily become disconnected.

My question is this: where can I locate the ground wire to the PCM, engine and any other ground wire besides the one located next to the battery?