well, in theory, if all the guages were hooked to the same power wire, they should all either stay on or off, but you know how cars are, so that statement could be completely wrong, i had my guages plugged into the constant on my TT harness, it killed my battery until i had a chance to fix it. it is still sitting in the garage as we speak, although the shootout and matt's car makes me want to go work on it. :-)