1969 original z-28--although the motor is now a gm crate small block.--while driving, the temp. gauge quit working. after investigating, i found the voltage regulater had stuck , melting the alternator wire. after replacing alternater. regulater and cleaning up battery acid and repainting a couple of places, the temp. gauge still doesn't work. i replaced the sending unit , but it didn't help.when i turn the ignition key to the on position, the temp. gauge needle pegs out to cold . any suggestions?