Only when raining/or snowing, the traction control light comes on solid indicating it is disengaged. The dealership has replaced all switches, sensors, modules and wiring harness. Three weeks ago they swapped the main computer from mine and it did not malfunction until today in the rain?
Any suggestions?

 

Since all was OK until driven in the rain, ffor atarters, I would make sure that all connectors have dielectrical grease on them, have their respective seals on them and are tight.

 

I think it's a bigger issue that, as mine is the third freestar at the dealership with the same problem

 

I would check ALL grounds. Ford transmits information back and forth to the various modules via the ground system. Check for any and all "GREEN" grounds. There are 4 cluster of grounds on the radiator support unbder the black cover. Ensure these are clean. There is also a ground lead on the A/C accumulator/Dryer bolt and a couple under the driver's side dash area. These can and will cause all kinds of GREMLINS in the Freestar.