The girlfriend has an 07 Sport trac with the deatc, last night she could not get the fan to turn off (besides turning the ignition off) when she would hit the off button the fan would go to high, she was able to turn it down with the controls but not off. first thing I did was check fuses, they are fine, So from the research I have done it seems that it might be the blower control module, apparently the regular eatc units have a resistor that could be bad, but read where the deatc units are solid state and controlled by the module, anyone have any ideas? the price of the module is around $85.00 where as a resistor would have only been $25-$30.00. I would just like to verify that these don't have a resistor, and if I am on the right track on this.
Thanks for any help.

 

They do use a solid state module.

Its essentially a high current MOSFET transistor. A blower motor resistor pack has three levels of resistance (and short) so that the blower motor gets different levels of voltage/current.

With the solid state module (transistor) the current/voltage is being controlled like a water hose spigot. The DATC is the hand turning the valve, the valve is the module, and the water is the current.

The reason for using these is that there is "infinite" ranges of current. Notice when the air starts to blower faster it is a smooth transition.

 

Ok cool man, so with the issue that she is having, do you think that it is likely that the module needs to be replaced? Thank you much.

 

Yeah its possible. I know some models had an issue with corrosion.

 

ok thanks for the help, I guess I know what I will be doing this weekend.

 

Update: Ok I got it fixed, Thanks again Anthony, it was the blower control module (resistor) had to order the part, but overall an easy fix but expensive part, took the part out and then the the new part came in it only took fifteen minutes and gf is happy she has heat again.