I wondered if some kind soul could point out where I'm going wrong with something ... I've been attempting to modify the circuit on my Td5, so that the rear washer switch becomes a rear wash/wipe switch using a m 4-pin relay.  The washer switch is a momentary live-switching switch, so I've used the live output from this  to power a relay, which switches the earth from the rear wiper relay.    The plan was that this would replicate the function of the rear wiper switch, which is a