turn signal problem
Having chased down all of this stuff myself, I was amazed at how many connections (positive, negative), relay internals, bulb sockets, body grounds were corroded. Literally took me months to go through all the circuits that were not functioning properly.
On the turn signals after fixing connectors, bulb sockets, bulbs and replacing the relay that was internally corroded - I had the wrong type of turn signal relay.
Did I say months? As I posted elsewhere, I got in the habit now of putting electrical grease on and around all connections to try to keep future corrosion away.
I heeded the advice here and the only real way to do this is to connect everything up the way it is supposed to be and test every single connection, positive and negative. i.e. You should be able to power the positive side of the relay and have blinkers. As well, I added more ground connections where I thought the factory connections were weakest.