Hello and welcome to Just Answer!
There is only one bulb on each side that lights up when you press your brake pedal.
Are both the left and right rear brake light bulbs not working or just one side?
Does the center brake light work?
Click here and here to see the connector and wire colors of the driver side tail light lamp. The connector and wire colors should match your van. I am at work now and won't be able to get back to you till later tonight.