How to Put a New Wiring Harness In an MGB | It Still Runs Putting a new wiring harness in an MGB was a consideration made by the car's company. Most of the wires on the harness will be fitted with the proper type connector for their use will also be the proper length and shape to reach their associated devices. Removing the old wiring harness and preparing the MGB MGB Wiring Harness Installation - British Car Forum Apr 29, 2013MGB Wiring Harness Installation New Members, Please Read - IMPORTANT!! If you are registering on British Car Forum, do NOT use "auto-fill" to fill in the registration form!!