Don't know for sure about '70, but if the column is similar to '72, it might be possible to change switch with column still in the car.

Steering wheel needs to come off. Then you SHOULD be able to feed the bottom of end of the TS switch harness plug and wire bundle back up through the wire tunnel that is provided along the underside of the column. Some have attached a flexible wire or string to the bottom harness plug, so that you have a way of pulling the new harness plug back down through the tunnel.

Check this thread for some pics...

https://board.moparts.org/ubbthreads/show...rue#Post7172387