I haven't experienced the exact same problem you're describing, but I have had a few different problems with ECC damper motors and especially the rheometer-type position sensors that are connected to them. You mentioned that you are seeing the REC and AC lights flash... that's a sign that the ECC un...

Have you performed the damper motor recalibration procedure?

When you have the motors connected to the car, leave them out of the casing and see if they move ok when you change the position of the air direction on the ECC. Do each one in turn. Some are a devil to get to as you are working blind, in particular on the RHS rear motor. I had a problem with our 93...

Should also add, the main cold air intake flap behind the glove box has a plastic arm on it that breaks. Fairly easy to replace but make sure the motor is in the correct position before fitting the arm. You have to remove a T20? screw from the motor and it should slide forward and out. I think the p...