This is the return path for the electrical current. It connects to the outer metal barrel of the plug. Blue Wire (ID/Data Pin):
| Connector Contact | Likely Wire Color (Dell OEM) | Voltage / Signal | |------------------|-------------------------------|------------------| | Outer barrel | Red or White | +19.5V | | Inner ring | Black or bare shield | GND | | Center pin | Blue, Yellow, or White | 1-Wire Data | 3 Wire Dell Laptop Charger Wire Diagram
and will refuse to charge the battery to protect the system. This is the return path for the electrical current