My OD Light started flashing on my 2003 ford e350 about 9 months ago and the van was shifting hard Ran the code and it said that it was a short or the solenoid. I replaced the solenoid pack twice and this did not fix the problem. I then replaced the computer and that fixed the issue. 5 months later the light started flashing again (this time there was no hard shifting) So I put another computer in there and after 4 weeks the light started flashing (still not shifting hard and light goes off after van is turned off).

Im really not sure what else to do here. The wiring harness looks fine. Any help is needed!

 

It would help if you could tell us the year, model, engine size .
Usually when the OD light is flashing it indicates a trans problem.
Were you able to have the computer checked for any codes? Many times it will help provide some direction and hopefully prevent replacing good parts which is not only expensive , but disappointing also.

 

Check and clean the harness connectors with electrical parts cleaner . Look for loose or broken connections. Do not scrape it with a screwdriver or anything metal as you will cause a short.