Heater And A.c. adjuster messing up

[tcgordy]

whether i have the ac on or the heat on it will only blow if it is on full blast, as soon as i turn it down a notch it shuts off. all the vents work properly, the feet, the face, the defrost. and when its blowing after a while the blow will star skipping. please help if u no wat it is , if not ill take it to ford but if its a easy fix id rather try it b4 i let them mess with my truck.

[tech10002]

It sounds like the blower speed controller has failed. It's a pretty common failure item on the 05-07s. It's under the hood on the blower box. Changing it is a bit of a pain, but it only takes about 20 minutes. You need to loosen the accumulator and pry it a little out of the way to get to the lower screw.

Here's a pic of it.

Attached Images

fanmodule.jpg (54.6 KB, 12 views)

[tcgordy]

thanks man, so i need a new controller?

[SCUFFY828]

Originally Posted by tcgordy

if not ill take it to ford but if its a easy fix id rather try it b4 i let them mess with my truck.

ill take that personal, considering ive already told you id look at it

[tcgordy]

Originally Posted by SCUFFY828

ill take that personal, considering ive already told you id look at it

no need to take it that way, i bought my truck from the old regal, you work over off parkway. i no parkway bought regal but i fig. i have to take it where i purchased the truck.

[SCUFFY828]

you dont have to take the truck where you bought , it , ive not been at parkway for almost a year , so just whatever

[tech10002]

It's most likely the controller, but if Scott will look at it for you, I would do that because it would suck to spend the 50 bucks or so on the control module and have it not be that. They typically fail where they'll run in high speed all the time no matter what the fan is set at. Yours has failed a bit differently. The controller is just a MOSFET transistor and some supporting circuity that varies the voltage to the fan. The transistor usually shorts, so all it will do is pass the full battery voltage. I've fixed a couple of them for friends by just changing the transistor. It's about a 5 dollar part and takes 10 minutes to change if you're handy with a soldering pencil.

There is a possibility it could be the main HVAC controller in the dash too.

[HVAC SuperTech]

I would say its the fan speed resisitor, mine was bad when I bought my truck. I replaced that part, I think it was 20 bux, and I was on my way. But, like said before, if Scott will look at it, let him. Hes the Man about SD's around these parts.

[tech10002]

His is an 06 Lariat, so he doesn't have a resistor. It's a transistorized electronic control. The 05 and up trucks without the electronic climate control still use a resistor, though.

[tcgordy]

thanks for the input guys.