I would like to know if the overdrive button can be wired to remain on all the time, this van at 45 mph shifts very hard almost slamming like shift, I found out that if overdrive is engaged that it shifts smoothly at that point, my brother who is a GM mechanic said he thinks that the torque converter is bad and kicks in causing the problem if the overdrive button is not engaged, I have sometimes forgotten to engage the button and now have a problem with it flashing and not wanting to engage.

Thanks, Glenn

 

The system is designed such that OD is engaged all the time unless the button is depressed , then the OD off lite should come on at which point it is disengaged. Anytime the key is turned off then back on the system reverts back to normal with the system going into overdrive when conditions , speed, load permit.

With that info can you please redo your question ?