In my first sentence I suggested that the turn indicator lights might be shorted together and you should pull the cluster plug to see if your problem goes away.
here's a diagram of the cluster wiring.
Terminals nine and ten are the wiring paths for the turn indicators.
The two wires should be light blue and dark blue at the cluster plug
Pulling the cluster plug will eliminate a short in the cluster, however there are other places they might be shorted.