05 Grand Caravan Lock Problem

I have a 2005 Grand Caravan with door locks that will continuously lock and unlock. They might go up and down 2 or 3 time in a row or as many as 15 or 20 times. It can happen when activated by the remote entry or starts when you reach the speed that activates the automatic door lock. It seems to be related to outdoor temperature. It doesn't do it in the cool mornings, but goes crazy when the outdoor temps get into the high 80s. The local dealer hasn't found the problem yet. Help!!!!!