Electrical problems and dead Tach

My '84 Rabbit Convertible's tach stopped working and along with that so did the turn signals, gas guage and water temp. I figure it must either be a problem with power to that half of the dash or a common ground.
Has anyone else had this happen, if so, what is a good starting point?

Thanks.

check the multiconnector plug on the back of the dash gauge and the fuses. try shaking the wire harness, if the gauges begin to work there is a bad connection somewhere. i'm fairly sure that the dash panel contains a 5 volt regulator, maybe that is not functioning.