yes, just splice it and make sure it is taped up or use heat shrink to cover it back up.
heat shrink rocks for wires!@!
the ciggy lighter should have black (ground) and a red (+ve). use them for the autometer light wires, and there should be another ground for the actual guage this can go on the black from the ciggy too.
pic of mine:
got lazy and didnt use heat shrink.