Did you see if any trouble codes have been set?
Key in off position, insert paperclip into pins A and B. Have notepad ready. Turn key to ON, NOT RUNNING. It will flash once, short pause, flash twice. That is code 12 indicating the system is ok. Long pause then another set of flashes. Each code is seperated by a long pause. Each code will have a short pause between each number.
Best to run the test again after you get your first set of codes to make sure you got them right. Let us know if you have anything besides 12.
2001 Bonneville SSEi (retired at 365,000 Kms.)
2014 Jeep Grand Cherokee Overland (yes, I know its not a GM)