Rod,
Once in a while my headlights won't go down either. What has worked for me in the past is; - Push in headlight switch (lights stay up). - Shut off engine (lights stay up). - Restart engine (lights stay up). - Pull out/Push in headlight switch (lights go down). I know the vac. system on my '79 is a bit simpler than yours' with the wiper door, but it's worth a try. HTH Kevin