Blower High when EATC OFF but Key On

[mbruffey]

HVAC blower stays stuck on high when key is on. Blower will not change speeds with the blower speed "wheel." Blower stays on high even when the "off" button is pressed on the EATC console. Blower does stop when key is off. Removal of fuse 9 in the engine compartment deactivates blower completely (key back on). Rest of panel still operates properly.

This is a 1997 Eddie Bauer 5.0 AWD with EATC. What's the solution? Thx, M

P.S. I think that I can figure this out eventually based on other threads, but I'm hoping that my description of the conditions is specific enough that some kind soul will offer the solution.

 

[mbruffey]

I'm guessing that the problem is with this component, but is the fault in the relay or is it in the transistor? M

 

[budwich]

check the relay with a meter, see if the contacts are always closed. IF not, then it is more likely that the "active component" (ie. trans) has failed.

 

[mbruffey]

Since it's probably either the relay (on the board) or the transistor, I'm simply going to pull that doodad and resolder all the connections. I had to do that in the console once when one headlamp went out—weird! Here's another link that might be helpful: http://www.lincolnforums.com/forums/threads/6966-Cheap-fix-for-EATC-blower-speed-controller M

 

[budwich]

I doubt soldering is going to change anything unless somehow a "run" crossed over some tracks.... but heck, anything that is free, is good by me. Good luck.

 

[mbruffey]

Back on line, at least for the moment. You need a 1/4"drive 8mm socket, some extensions, and a u-joint. Flip the cruise control module out of the way and you can remove the blower motor control module, with some patience. Then you need a #10 torx to remove the board from the surround. You might want to have some isopropyl, simple green (for the case), and a few q-tips handy. Don't forget to clean out the inside of the case. Cleaned and reinstalled, the unit is working fine. We'll see if it holds up.

That stuff piled up inside the case was a little damp. Hmmm . . . . Maybe I shouldn't hit those giant puddles quite so hard? But then, how am I supposed to get all that road salt off?

In case you want to see what I cleaned out:

 

[mbruffey]

A few more pics:

 

[mbruffey]

Still working after several weeks. Checking off as a genuine fix. M

P.S. For clarification, I did NOT resolder anything; just cleaned off the components.

 

[tgibbonsfordluv]

My XLT does this too, but I believe it's normal function. The blower shuts off when I reach behind the console and turn off the rear HVAC. If I leave it on in the rear and turn off the main switch in the front the blower still runs.