The stock horn wire can ONLY be removed from inside of the car unless the horn wire has been cut inside the car which ruins the horn wire.

The original horn wire has the contact for the horn button crimped onto the end so the only proper way to remove or install the horn wire is from inside the car and it's critical to the longevity of the horn wire that it be 1 continuous piece of wire without crimp connectors to splice it together.

Reproduction horn wires are available and so are the special Lucas style bullet connectors for the engine bay connection.

If you plan on using the original steering wheel and horn button, I hope you still have the spring, insulating sleeve and thin split washer that holds the horn wire in place where it comes out inside the car as they need to be reused if you want to use the only available reproduction horn wire.

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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com