There is an undersized power wire that runs from the ignition switch
into the column harness just below the steering wheel. Remove the
cover from the bottom of the column between the trun signal and
ignition switch and inspect for a melted or burned wire attached to
the switch. I attached an additional jumper wire at the switch and
supplemented the factory wire for a few inches. It seems that the
"tilt wheel" flexing up and down causes this to happen quicker.

Good luck, Bruce