1971 Corvette Headlamp Door

The left Headlamp door on my '71 Corvette comes up very slowly, or sometimes not at all when I turned on the headlights. Vacuum lines appear to be ok, could it be the boot on the actuator rod that is failing? I'm trying to figure where to start first with my troubleshooting. Thanks
Piepmeyer

it sounds like the seal on the actuater is leaking. i had to replace mine. now everything works great. good luck!