You can narrow it down by taking a jumper ground wire straight from the negative post on the battery to the tins on the gauge cluster but you said tach dash... sooo. Does the tach work? If yes I'm thinking bad light switch (resistor in the switch to dim or brighten dash lights by turning the switch knob). If no, then bad ground (seen this burn up tachs
). Jumper wire from battery to cluster tins should confirm if the cluster isnt getting ground. Simple connections to check are 1.ground clip to dash- clean with sand paper to bare metal. 2.cluster wiring connector terminal to circuit board. 3. The connections Lockdoc mentioned. The gremlin that I can't wrap my head around is the turn indicator flashing opposite sides so I'm stumped on that one. Hmmmm.