Front heater fan will not work on low

Actually it will only work on high but not on any lower speeds.
high speed bypasses this assy.
the blower motor resistor assy is located behind the glove box and
needs to be replaced.
just lift out the glove box and it is on your right side.
part is only available from a Chrysler/Dodge dealership, relatively inexpensive ($30) and easy to replace.(remove 2 hex head screws with a socket or nutdriver)
An amateur can do this!
New part has a one year warranty, keep the receipt it you might need anotherwithin 12 mos.
Have found that replacement parts never last as long the originals.
Have replaced mine 3 or 4 times now my 14 year old can do it
if I am away.

I have the same van and i just fixed the same problem by buying a new blower motor resistor

Burn that VAN ! !