Got a autoguage tacho but i dont know how old it is, anyway on my way home today i noticed the guage was way past hot, so i pulled over and checked the motor and it was fine, not hot at all, i then turned my ignition on and the temp guage shot up so fast to hot, i did this a couple of times and it did the same thing, does this mean the sender is gone? also is there a place to put the sender or is just where ever the guy i brought it off wanted to put it?