HVAC fan speed

[Growingupwithponies]

06 4.0 Convertible. Automatic. Son’s hvac fan speed was only running on #4. I swapped out the resistor. Fan changes speeds on 1,2&3 but #4 runs same speed as #3. Any suggestions? I tried the relay under the hood with a know working relay. No change.

 

[MrBhp]

My guess is a Chinese resistor or faulty control.

 

[Sloane]

If speeds 1–3 work but 4 matches 3, the blower motor or its wiring for high speed is likely the problem. Check the motor connections, and if they're fine, the motor may need replacing.

 

[Growingupwithponies]

I will check that motor and wiring out. Thanks for the suggestions

 

[VistaBlue09]

It could be a faulty part. Try a Motorcraft brand blower motor resistor to see if the issue persists.

 

[86GT351]

It could be a faulty part. Try a Motorcraft brand blower motor resistor to see if the issue persists.

This