2001 Grand Prix electronics
 

I own an 01 Grand Prix GT, it has electronics problems. Can some one help isolate these problems:
1. Shift indiccator light in cluster works sometimes.
2. If P indicator is not illuminated, the key does not release.
3. Brake warning indicator stays on some times.
Any help would be appreciated, I took to GM dealer, he said the shift cable needed to be adjusted. No help there.