Instrument Cluster, Ground Issue??

Hi, on my 73 Duster, when I honk the horn my right and left turn signals, the oil light, and the seatbelt light on the gauge cluster flicker for like a second. Would this be a ground issue? The lights will also flicker some times even when I don't press the horn, its random. The cluster grounded to the dash, through the screws right? Would adding a ground wire help solve the problem?