I have had the dash apart for weeks, The headlight pull switch failed. I got a new one from Charles Fares. Thank you Charles!! The speedometer failed, There are a few places where this problem could come from and this one was a bad cable from the transmission to the cruise control unit. I pulled the standard steering column out and installed a tilt column with a recast steering wheel (thank you Jason and Russ!!). I had melted AC and heater conectors – I replaced these. Along the way I replaced bulbs and such. I did NOT replace the dimmer switch – it the tilt different than the non-tilt. Now the dimmer switch on high turns off the instrument lights
Why would this happen? Non-tilt dimer switch? I forgot to plug something in? Any ideas??
Since turning on the hi beams also turns on the hi beam indicator bulb in the instrument panel I would look for issues with that light. I would remove that light and light base/socket from the back of instrument cluster, remove the bulb from base, tape off the bulb base so it does not touch metal then try your high beams. If hi beams work, and rest of dash lights stay one, I would test the bulb out of the base, then inspect the light base. Perhaps the bulb or base is causing a short. Before chasing anything else, that would be the most obvious place to look first.
you have a bad ground on the instrument cluster lights.