Do any of you guys remember a trouble shooting aid called the tattle tale? it was to be wired in paralel to a suspect switch so if that switch opened the voltage would go through the tattle tale and it would burn open so you knew that switch did in fact open. I had a problem with a boiler a while back, and had to narrow it down from about five saftey devices. some of these would have come in handy. Do you know of anything similar being sold today?