Vertical blinds glide and rotate on the carrier clips found inside the head rail. Carrier clips are made from plastic and have few movable parts. Sometimes the carrier clip does not allow the vane to rotate when operating the blinds with the wand. Fixing vane carrier clips might require replacement parts which are available through the blinds manufacturer. The general process for repairing and replacing the carrier clip is the same across brands.
Open the vanes of the blinds with the wand. The vanes should be pointing toward the room.
Hold the vane that attaches to the faulty carrier clip with your hand close to the clip. Slip a credit card between the carrier clip and the vane. The credit card raises the vane stem hook away from the vane. Gently pull the vane down and put it out of the way.
Grasp the front and back of the carrier clip with your fingers. Push the carrier clip stem toward the wand until it unsnaps from the carrier. Check the small teeth around the end of the carrier stem. If they appear worn or stripped, replace the gear.
Pull the carrier gear out of the clip. The carrier gear is the flat piece of plastic that mounts inside the solid side of the clip and has ridges. If necessary, pry the gear out with a small, flat-head screwdriver. Sometimes the vane doesn't turn because the gear has dislodged from the clip.
Inspect the gear for damage or extreme wear. The gear ridges should not be smooth or flat. If the gear is worn, replace it with a new one.
Insert the carrier gear into the clip until it snaps against the side. Snap a new stem into the carrier until it locks into place.
Align the slotted hole on the top of the vane with the carrier clip. Push the vane between the slotted stem until the hook on the stem locks into the slotted hole on the vane.