One problem related to power door locks not working has been reported for the 1999 Dodge Grand Caravan. The most recently reported issues are listed below.
Intermittent loss of all dashboard indicator lights and gauges. Electric door locks will not work. Sometimes all malfunctions will clear themselves, sometimes I must slap the top of the dashboard with my hand several times to clear the malfunction. I have only seen this with vehicle in motion and on all roads.