Hi im new to the forum. I have a 1972 cutlass supreme im fixin up right now i have the front fenders off while im doin thefront suspension. The other night i fired it up but the headlights would not come on. The highbeam indicator light on the dash is lit blue. I can press the dimmer switch on the floor wich does nothing i have no power to the high or low beam bulb plugs. I removed the dimmer switch on the floor and tested the female plug with a multimeter to find 12v. but with the dimmer installed to the plug i have no volts. I figured the dimmer switch to be bad so i purchased a new one. It looked a little different out of the box but conections looked the same. As soon as i installed it high beam indicator light back on and still no power to the headlights. Any tips thanks!

 

Check headlight fuse in the fuse panel. Check headlight switch in the dash. May also need to trace the wiring from the headlights to the switch.

 

Welcome to the site!
The fuse in the block is for running lamps and not the headlights.
If you have juice lighting the blue dash indicator, then the headlight switch is supplying headlight power.
Since you removed the fenders, check the connectors where the lamp harness connects to the fuse block on the firewall. There is a bolt in the center to loosen first.
Also make sure the lamps as well as you meter is contacting a solid ground point.