CharlieS
GOLD Star
If you slide under the vehicle on the drivers side just under the b-pillar/rear door area, you’ll see a metal shield bolted to the inside of the frame rail with two holes through it, through which you could turn the shutter valve screws. If you remove that shield (12mm bolts, iirc), you can spray LPS3 on the valve body and screws (or smear them with marine grease).