On the overhead panel there is the Light Override Switch which is the same as pressing SHIFT+L. See '707 Captain' FLIGHT MANUAL Part II – Aircraft and Systems, page 51:

O20. LIGHTS CONTROL

2. Light Override Switch
OVERRIDE – Turns the lights located under the Pilot’s light shield and Engineer's panel fluorescent flood
lights to full intensity

It also turns on the passenger cabin lights.

Hope this helps

Mark