Sigh, I was out driving my car today, and now my hold light is flashing. Won't upshift from 2nd. It was working fine this morning though. If I shut the car off then start it back up the hold light won't flash, but drive for a minute or so then I feel a weird shift then the light comes on. Could this possibly be caused by something getting wet from slush or snow? Been pretty slushy here the past few days. My mom had an 89 Mazda MPV with the JATCO automatic that did the same thing, turns out it was a module or computer up in the RF fender that was getting wet.

 

I can't say for sure, but I'd guess it might be a solenoid problem or like you said, a connector getting wet. If the fluid is in good condition , as in no burnt smell and red in color the trans is probably still fine. I would find out what is making the hold light come on, might be a simple repair.

 

Looks like you may have guessed right. It sat overnight, and this morning I took it up the road and it's working properly now. I drove it around til it reached operating temperature. Now, last night when it was acting up, within 5-10 seconds of starting the car the light would flash. This morning it didn't flash at all.