heater blower runs on high only on 1996 Dodge Grand Caravan

Runs on high speed only.
Nothing on the lower speeds
fuses good
relay good
switch was in same position when it quit
occurred when i stopped at the store

Asked by for the 1996 Dodge Grand Caravan
the most frequent problem i have ran in to with those conditions is the blower motor resistor block. the high speed power does not go into resistor block, it has its own power. replace blower motor resistor block to fix that concern.
2 answers
When the blower runs only on high it's usually the blower motor resistor. The 1996 and 1997 Caravans may have an issue with corrosion on the connector terminals on the resistor. Look for any corrosion on the terminals. Dodge has a revised resistor and a replacement wiring connector.
I searched google and this page has great images of the condition. I hope this helps! You'll need to copy/paste that entire link I'm afraid it didn't copy correctly.