Damn, transmission problem

[Infinitrium]

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.

[Doug Tatham]

Check out this website, it might help:
http://autorepair.about.com/library/a/1f/bl662f.htm
It concerns pinched solonoid wires. If they are exposed, slush may be a problem. It gives guidelines for testing

[Infinitrium]

I read that one a few nights ago while doing a lot of searching on my car's problem. It mentions pictures a few times, if I could see those pictures it would be a help, but I don't see any link for them.

[Doug Tatham]

Check your engine codes, a lot of the electrical problems will show up as engine codes errors. If you don't have a code reader go to an autoparts store, they'll usually read them for you for free. You can do serious damage to a trans if certain solonoids aren't operating.
BTW the flashing over/drive light is very frequently an indicator of a short.