I am having issues with my 08 expedition, turn signal. The left turn signal works properly in the down position. However when completing the turn and multi function switch returns to middle position the left turn signal remains activated. When multi function switch is in the up position, i get no right signal activation. So i have been driving with lever in up position and when making left turns signaling, but then returning to up position. Flashers work properly. I replaced multi function switch today but have same issue. Any ideas?

 

Activate the hazard flashers and look at all 4 lights. Are they working properly?

 

Hanky, they are all working.

 

It sounds like a poor ground connection. To eliminate that possibility check all the ground connections . Do all the stoplights work correctly?

 

Stop lights all work. Tried wiggling wireharness while turn signal was in all three positions but everything remained the same. Unplugged multi function switch while in neutral position left signal flashing, and after unplugged left signal remained flashing, not sure if that means anything. Is there somewhere I would be able to see where all the grounds would be located to check.

 

There are many grounds to check, but I would like to get a little more info before I send you on a wild goose chase.

If you turn the key on, without starting the vehicle, then turn the left signal on and manually move it back to the neutral off position, it should still stay blinking if this is correct , just turn the key off wait 5 seconds then turn the key back on. What result do you get, did the flashing stop, did it continue ? If the signal continued flashing We would pursue one path , if it stopped we will choose another path.
I hope you don't mind doing these tests, but there could be two different possibilities and we will try to get closer to whichever (circuit) one "might" be involved. There are some weird things that can happen when electrons go where they are not supposed to go.

 

They stayed on, and thanks again for any assistance you can offer

 

Something that has power available to it with the key off could be providing power to keep a relay activated. A good place to eliminate would be the rear wiper that gets power to go to park position. Have there been any problems with that feature lately? Any problems with the automatic door locks? Have you noticed any things staying on when they should not ?

 

By on position w/ignition (for the test) did you mean one click over, or two which puts it just before veh starts. One click over the rear wiper works but turn signals don't. Two clicks prior to engine start turn signals activate. As far as anything not functioning as it should, nothing comes to mind. Wipers, radio, fan seem normal. I should note that when issue first started when turn signal switch was in neutral position they had a mind of their own would go from left signal to right signal without ever touching the switch.

 

Something does not seem right here. Rear wiper If I remember correctly should not operate with the key off just as the turn signals do. I suspect there is some problem with the rear wiper motor or the wiring. The turn signals just happen to be the path the defect chose to show itself. I wouldn't rush to change the motor unless when disconnected the problem is gone.