The switch is probably fine. The culprit is the resistor unit it is mounted in the air duct near the fan
truck blower only work on high
A blower motor that only works on high is normally caused by a defective Blower Motor Resistor Pack. DRL, do not have a clue.
from what i have read it is the blower motor resistor it goes bad and only lets the fan run on high google blower motor resistor and read on
Your blower switch sensor is out. Replace it!Then all the speeds will work
either the blower control switch or the blower motoer needs replacing
blower motor resistor needs to be replaced
it's a problem with the blower motor resistor,
faulty blower motor resistor
replace the blower motor resistor
Blower Motor Resistor is bad. 20.00 part at AZ.
If you are saying the Blower Motor only works on high, then your problem is a defective Blower Motor Resistor Pack. Replace it.
If you are referring to the blower motor only working on the high speed setting, then the problem is the blower motor Resistor Pack is defective. Replace it. It can be the blower motor speed control switch but not likely.