'75 Vacuum Headlights

Hi all,
My headlights no longer go up and down with the light switch. They will go
up and down however with the little switch under the steering column. I
have replaced all vacuum lines for the headlight system forward of the
firewall. By blocking the right actuator and relay, the left side pops up
and down like new. Likewise when I isolate the left actuator and relay.
Operating together they won't pull the lights up or down, even tried
squirting WD-40 in the relay ports like suggested here long ago. The only
thing the light switch seems to do is get electricity to the lights. Any
ideas on positively isolating the headlight switch as the culprit ? It
looks like a bear to replace (standing on my head for several hours).