Blower fan only works on high speed

Hello,

This could be a problem with your Blower Motor Control Module. I have included a link to a guide down below.

https://www.2carpros.com/articles/low-or-no-air-flow-from-vents

I have also included instructions for troubleshooting your specific vehicle in the diagrams down below. Please go through both of these and get back to us with what you find out.

Thanks,
Alex
2CarPros

My 06 GMC trucks ac blower motor is acting funny. First the high speed stopping working, now the blower works every now and than like when it just won'ts to. I have been told that it could be the resistor. Could this be the problem and were and how can I check it out.
Carl

you need to disconnect the wire going to the blower and put a test light there to see if it is getting power on each part of the switch. If it does then it' s the blower, if not then you need to check your switch to see if that is sending the power to the resistor. If it does then it's probably the resistor. It is a rectangular block that isn't easy to change, as it right by the blower motor...

Fan control has stopped powering blower starting with speed 1& 2, after a year 3 stopped now4 has syopped I only have the highest setting, #5, that works. switch problem or further

Sounds like it might be a blower motor resistor card the way the certain speeds stopped. Sometimes the connector to the resistors also melt to the resistors and need to be replaced as well. Unless you have a multi meter and want to do some testing with me i cant tell you for sure its the resistor.But my first thought would be a bad resistor.

do not have anything on 1 thru 4 fan speeds only on 5/high speed. how do I fix this

Replace the blower motor resister

where is the blower motor resister

It should be mounted on the HVAC box under the dash

new blower motor installed. The AC gets cold but when changing speeds from low med high, etc. the fan speed increases slightly. However on high itseems like it is not blowing very hard.

if the blower motor is indeed working but you don't believe that it is pushing air out as much as it should for each speed it may be due a broken/loose vacuum hose. you will want to check behind the dash for a vacuum leak.