The screenwasher pump on my SLK has stopped working after the car has been unused for a long time. The pump motor if fine, but the electrical feed to it has a strange problem. I've unplugged the two wires which connect to the motor. One is the earth, and the other has a voltage reading of 4.31v all the time, whether the ignition swich is on or off! Operating the screenwasher control makes no difference to this reading. Any ideas? Does the screenwasher circuit contain a relay? Does the feed to the pump motor come directly from the switch on the steering column? I'm thinking that if it does then I can connect a wire directly from the switch to the motor to eliminate any wiring fault between the two.