If you are attaching a new "pigtail" (a replacement plug with a short cable), you must match the colors. However, third-party pigtails don't always use the same colors. Always use a to verify:
Plug the charger into AC power.
Understanding the internal wiring of a Dell laptop charger is key for anyone attempting a DIY repair. Most modern Dell chargers use a 3-wire system to provide power and communicate with the laptop. The 3-Wire Breakdown 3 Wire Dell Laptop Charger Wire Diagram
Disclaimer: Working with AC/DC power supplies involves risk of electric shock or fire. If you are uncertain, consult a professional. Always unplug the charger before stripping or soldering wires. If you are attaching a new "pigtail" (a