Will this plug straight into my factory wiring harness?

Yes. This uses the original connector and electrical contacts—no splicing or adapters needed. Unplug the old switch and seat this one into the door panel cavity, then plug in the harness.

Do I need to remove the entire door panel to swap this out?

No. The switch panel typically pops or unbolts from inside the door without full panel removal. Check your owner's manual for the exact release method for your door configuration.

What if the switch works intermittently after install?

Check the harness connector for corrosion or loose pins—common culprit in older vehicles. If contacts look clean and tight, the motor or regulator assembly may need attention separately from this switch.