With the pull out head removed (or reinserted upside down so that the word “OFF” is visible), the power is now off to your HVAC unit, and you can safely work on the unit.
When you have completed your repairs or maintenance, to restore power to the unit, simply insert the pull out head back into the slot from where it came. It should go in with just a little bit of effort as the contacts go back into the housing. If it slides in too easy, check to see if it’s been installed upside down.
Close the door to the disconnect box.
If it’s a warm day and the AC was running prior to your maintenance work, the unit should start back up. If not, turn down the thermostat so that the AC kicks back on. Listen out for any odd noises.
Should you be experiencing any issues, reach out to the pros at Dallas Heating and Air Conditioning.