Ok I have been fighting this for a few weeks not. When I turn on a turn signal, it works just right in the front. But both lights blink in the rear. Same thing if I turn on the other one. So I pulled the switch out and tore it all the way down to see if I could find a short in it, but it was fine as far as I could tell. So I went and got one at the junkyard today. Plugged it in and it does the same thing. Both rear lights blink.
I took a test light to the wires and back probed them.
On the C104 conector I am getting power on K all the time. I know its the emergency flasher line. I get power on G all the time, but have not found that in the FSM yet. Must have something to do with something else. H&M are the left side flashers front to back respectfully. And J&N for the right side front then back.
When I push the switch one way or the other Both M&N always flash while H&J only flash if they are supposed to.
I feel like it should be something in the switch, But I just can't believe that I have 2 with the very same problem. The one I started with was working well in the garage a few weeks ago. I had it out for a run a while back and put on the Eme. flashers to see if all the lights were working and the next day I see that both rear lights always flash. I back probed with the key off and with the key on but no signal turned on. and did not see where there is any back feed power that I can see.
One thing I just noticed that I had not mentioned is that the P wire for the brake switch is always flashing also. I don't know why. I don't think I have a problem with brake lights. But I have not been out of the driveway for a few weeks not. Need to get the steering wheel back on someday soon while I still remember how it goes together.