I see what you mean. I have had a look at the webasto timer I have - it is just a switching contact, I can switch + or - as needed. It does stay on though after being activated. I was thinking of using a 555 circuit to give me a momentary pulse for your electronic gubbins, but I might program a 12c508 pic micro and stick it on a bit of vero board to do the same job. What do you think?