At least 2 or more things come to mind. Check the battery terminals for dirt.

The rough idle, etc may be due to a vacuum leak. 1st suspect would be the vacuum line on the passenger side of the intake manifold, wrap it in electric tape to eliminate it as a source. There could be other vacuum problems, so look around at anything coming off the manifold. Take the cover off the throttle spring and check the connection at the vacuum tree.

The turn signals... check the fuses first, I think the power rearview mirrors are on the same circuit.

And stop by and atuozone or pepboys and get any diagnostic codes read and deleted. You may want to have a pen and paper handy. Delete all of the DTCs and see if any come back right away.

Klaus
--
Please answer, we need to know if the advice is good or bad. The 164 has a new home, all I am left with are 2 turbos :)