Bad fan switch - only works on 3 & 4

[mcpear]

The fan only works when the switch is on 3 or 4. Is there an module under the dash or in the fuse box that regulates the voltage or is the switch bad? Thanks.

 

[ELVATO]

What year is your Expy?

This is what I have listed for the following symptom for an 00 Expy:

No operation in lower speeds — manual climate control

And these are the possible sources:
-Circuitry short/open.
-A/C blower motor resistor.
-A/C blower motor switch.

For an 03 Expy, the sources are the same, but the way to test it is slightly different.

 

[mcpear]

2003 XLT

 

[ELVATO]

Edited my post.