99 Mountaineer 5.0 with lots of DTCs

[newstylecustoms]

My son swapped the switch and no effect on the problem. But the problem seems to be changing. When I first started the truck yesterday the left turn signal worked properly but it still flashes the dash lights with the turn signal. After the switch swapping now the turn signal does not work at all. I need to spend some time probing wires and making sure they are seated properly. I have not yet done anything with the flasher.

 

[poker4me007]

Just a thought, do you have a trailer wire harness on there? Iv'e had one of them plug in inline ones go bad, and mess with the blinkers.

 

[newstylecustoms]

Yes there is one, Good point.

 

[Turdle]

driver side not flashing but do both turn signal lights front and rear illuminate? Have you tried a new flasher?

 

[koda2000]

You may want to check for bad grounds. I've seen all kinds of strange things happen with bad grounds.

 

[1998Exp]

My son swapped the switch and no effect on the problem. But the problem seems to be changing. When I first started the truck yesterday the left turn signal worked properly but it still flashes the dash lights with the turn signal. After the switch swapping now the turn signal does not work at all. I need to spend some time probing wires and making sure they are seated properly. I have not yet done anything with the flasher.

Koda already mentioned it, so I will just reinforce: there is a long history of the contacts pulling out of the gray, moon-shaped connector at the MFS, because of the tiny protrusions inside that hold the contact pins breaking off. It may not be obvious until you tug on a wire and feel it loose.
The problem was so common on Ford trucks that there are several brands of aftermarket pigtail connectors available. The steering wheel gets in the way, so I pulled it off before soldering the wires. Conventional steering wheel pullers don't work on some versions of the Ex steering wheel (probably the higher trim) because there are no threaded holes, so you may need a gear puller. Don't remove the bolt completely; just loosen it a couple threads and use it to support the puller shaft, because otherwise the shaft will sink into the threaded hole in the steering column and damage it.