2001 Chevy Tracker - All lights dimming

For 8 or 9 months now the dash lights and headlights on my 2001Chevy Tracker are dimming (more like flickering but they don’t go completely out). It is not the alternator - it has been checked. For a period of 4 orso months in between the beginning of this and now - the dimming stopped and now it’s back. The only thing I can correlate to the dimming stopping was I had to have my car jumped because I left the headlights on and the dimming seemed to stop for the long period of time. Anybody have any suggestions?

When they checked the alternator, did they also check the battery?

How long ago was that?