Need advice. Just finished helping a friend with a rusted out gas tank in his 1982 by installing a 1984 tank. However there is a two-wire connection for the '82 and a three-wire connection on the '84 tank's fuel-level sending unit. Since the tiny screws almost always break off, we do not want to try to swap out the different sending units. Which wires from the '84's unit do we attach to which wires of the '82 harness?