Did you know you can use your turn signal switch as the overdrive switch?

For USA delivery cars, the momentary switch function of the turn signal switch that is used in Europe to flash the headlights is wired, but not connected to a relay and you can easily connect you overdrive wire to it.

I like to do conversions like this in a manner that could be easily reversed, so I would change just the end of the overdrive switch wire by splicing on the correct end for the turn signal switch from old harness' which I have and then plugging it into the turn signal switch.

FYI, the connectors for the turn signal switch are a special bullet style connector and are not available at any electrical supply store that I know. However, the Volvo 122 and 544 used the exact same style of bullet connector.

Another FYI, be very careful when removing the bullet connector from the turn signal switch as the fiber board on the switch can be brittle and on rare occasions I have broken the connector right off the switch. Although expensive, a high quality reproduction turn signal switch is now available.

But you can just cut the existing wire from the turn signal switch, which is the purple/brown wire, and butt splice crimp it to the overdrive wire and if you want, you can perform this modification without pulling the wire off of the turn signal switch by cutting the purple/brown wire further down the harness under the dash and running it over to the overdrive wire at the dash.
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Eric

Hi Performance Automotive Service (formerly OVO or Old Volvos Only)

Torrance, CA 90502