My 2004 gmc envoy's dashboard lights wont turn off ( abs I Parking ) and the air wont work.

Curious as to the battery and alternators state and condition low voltage or poor charging can cause un-explained faults-is the check engine light on?-if so can you get or retreive dtc's as i'd like to know what you pull for codes. fyi most parts stores will retreive codes for free....some even grant access to mitchell on demand or all data to help diagnose probable faults or at least steer you in the right direction.