88 iroc gauge problem

when i turn my headlights on or park lights on my tach freaks, oil pressure and volt meter go limp and my right inside turn signal glows,,,,i turn the dash lights down to the off position where headlights are on dash is off my gauges work,,,,,replaced the headlight switch, no fix,,, anyone have this problem or heard of it ??? where the hell do i start??? any help would be appreciated



thanks
kris

It's time to clean and check all of your under dash grounds. While your doing those might just as well do every ground you can find. Use new star washers where needed and anti corrosive on the others. Sounds like a bad ground in the lighting system and it wants to gound through the tach.