does anyone know what can cause the fan to blow on one speed?
heater and a/c work fine but it blows same speed no matter if it is set to auto. please help

 

Sounds like a bad blower resistor

 

what do i have to replace ? the blower motor or is there a relay or something.

 

Bare with me here because I dont' know how to put this in writing easily ... When you set the A/C on auto mode it's going to blow at full force until the temperature inside the cabin reaches the temperature you set on the screen. For example if you have the temp set at 65 degrees and you select the auto mode, it's going to blow at full force with the coldest air possible to lower the temp to 65 degress, once the temp gets down around 65 the blower will slow itself down ... The best thing to do would be to set the blower speed manually ... I hope this helps

 

even if i set it manually it blows high all the time no matter what speed it set to. it will blow hot and cold but always at the same speed

 

take it to the dealer to look at it.

 

Mine does not behave this way. If I have an extreme temperature difference then the fan will blow at max like your example but, as the cabin temp nears set point, even as much as 10deg it will start to slow.

I agree with the resister being bad and I would say that it is shorted, not open.

BP

 

Sorry that's what I meant to say, As the temperature nears your selected point it will begin to slow itself down, thanks for stating it more clearly for me ...

To the OP, ok then there is something wrong there, take it to the dealership or a reputable mechanic, you don't want a/c on full blast all day that's an extra waste of gas