Hi, I do not know the model, look under the bonnet towards the lower end of the Windscreen, there should be what you say a black removable cover, Before you start this with your wipers switched on try the i different speeds, are they all OK? you said the motor is working!! can you hear it? if that's the case the probably cause may be the connecting wiper arms, check that the nut is tight, if they are OK the next thing to check is the link rods within the bulk head, they connect via a connecting snap on ball effort ( Its not a big job). the result will be interesting.