Did a search on this site could not find a similer problem.
The entire turn signal circuit (interior and exteior lights), tail light and after market tach stopped working. Brake lights and headlights work fine. Checked the fuses and they're good. Could it be a bad ground somewhere? Not sure where to start to try to troublshoot this. Appreciate any help. Thank you

68 camaro 327 mostly stock.

Using a test light or voltmeter check the BAT, IGN, and ACC terminals on the fuseblock. BAT terminal should have power all the time, IGN with key in run position, and ACC in run or acc key position. If these check out probe the fuseholder clips (not the ends of the fuses) on both ends to see if you have power. The clips can get corroded and even though the fuses are good the circuit will be dead at one end. Let me know what you find.

Check that you have power to the turn signal switch, all lights power are drawn from there. Do you have parking lights, if you do ground circuit should be OK, sounds like possibly the power that goes to the turn signal switch may have been "tapped" for the power for the aftermarket tach. Also check fuses with a meter (not just visually) as I had a few fuses blown far left or right that you could not see, meter said it was bad and after pulling it the metal cap fell off on one side right where it was blown... :confused:

Update - Fuses are all good (checked with a meter). The problem I had was no power to ACC terminal. I traced it back and found problem. Thanks guys for all your help.