air conditioner only work on high on 2002 Dodge Grand Caravan

hello can anyone help me please!! change already three times the ac relay and keep doing in it!!

1 answer
The blower motor resistor is bad ($13 at any autoparts store). The resistor is located under the pass side dash panel near the floor and has a bunch of wires leading into a removable unit. There are 2 screws that have to be removed, pull the thing out, unplug and replace with the new unit. Takes 5 minutes tops. Need a hex socket (#10 ish??) to take screws out.