English to French Tech/Engineering Construction / Civil Engineering Door mounting

Hi all,

First I thought this had something to do with electricity since this industrial curtain is supposed to have lights to indicate movement, but it appears it has nothing to do with it.

Here is some context:

"Release the brake and guide each outside curtain bulb between and behind the roller guides. Slowly lower the curtain to the closed position, verifying that curtain buttons and bulb are not tight. Raise the curtain to the full open position to see if the curtain telescopes in toward the center of the door when rolling up. If contact between the curtain bulb and re-feed roller occurs, the curtain will need to be shimmed."

Many thanks for all your suggestions!