I have a CDI furler on my O’Day 322. It has an internal wire halyard.
On my boat, there is a “car” in one of the foil grooves, that is pinned with a cotter pin about a foot or 2 from the bottom. The other end of the halyard is attached the top of the sail.
To lower the sail, first attached a strong messenger line to the “car”. Then carefully remove the pin. It would help,to have someone hold the car from flying up as the cotter pin comes out (I got hit in the eyebrow once…).
Then ease the messenger and pull the sail down.
To raise the sail, a secret I found on mine is to thread the messenger line (you will be pulling it down from the top of the foil) through the little turning “block” at the bottom of the furler, then you can pull up on the messenger, keeps the pull exactly parallel with the foil.
If the car and foil groove look really dry, you can either use Sailkote or even some grease to lubricate the car in the foil groove.
My CDI may be a bigger version than yours, but hopefully these notes are helpful.
Greb