No floor heat?

[F150canuck]

I see lots of heater issues on the site, but I have a great defroster and the A/C works in the summer just fine. My issue is that there seems to be no floor heat? I am going to tie into it, but thought I would ask first before venturing into the "final frontier". Thanx

[Rambo67]

I have the same problem with my truck. It's like there is somthing not opening or closing to direct the heat to the floor. I have had this problem for a couple of years and my wife always brings ti to my attension when it gets cold. I have never looked into it, but would like to get it fixed.

[NFBill]

My 2003 SCrew is the same. Everything else works fine, it just doesn't switch to the floor.

I had a mechanic check it out, and apparently, that module that switches the vents costs something like $900 - not including installation.

He has or had the model number for it marked down for me to search for something cheaper, I left without grabbing it!

I'll see if he still has through the week and maybe take a boo around the internet and scrap yards.

[willy700]

My 2003 KR does not have floor heat either and funny thing my wife reminds me every winter also.

[ztohs]

Did anyone find a solution to the no floor heat problem? I see references to "good pictures & descriptions" about this problem in other posts but I can't find these grail posts easily.

I have good temperature control hot to cold. I just can't get the heater output to go to the floor. It must be the mode door and I'm digging into the dash today searching for it. I found a vacuum actuator with a red line that apparently controls flow to the vent. There must be a similar one for the floor selection. Apparently this is #20 in the image from:

http://www.fordf150.net/forums/viewtopic.php?t=58092



Any help would be appreciated. I know I'm going to tear way too much dash apart in the hunt. Thanks!

[ztohs]

I signed up for a 72 hour access at helminc.com and found info on where the floor/panel actuator is located and how to remove it. I took a whole lotta dash apart which in the end wasn't necessary. I found the actuator and learned that it's a three position actuator with two vacuum line connections. One line pulls the diaphragm halfway down when connected to vacuum to enable the panel/floor setting. When the second line is also connected to vacuum, the diaphragm gets pulled down the rest of the way. Anyway, both worked when vacuum was manually applied so it isn't the actuator. I also found the door itself was fine when moved manually. I guess there's a problem with the blend door that is actuated with a stepper motor and driven into its mechanical stops whenever it self calibrates. Luckily that hasn't failed for me.

Next I wanted to test the lines and the back of the EATC is a convenient place. I used a tee and two unions from the hardware store along with some fish air-pump tubing to jump black (vacuum source) to blue and yellow. I was able to control both. This meant that the EATC was the culprit - not applying sufficient vacuum. I'd seen another post about o-rings that go bad and I gave it a shot. Sure enough it worked. While I had the EATC open, I also tested the solenoid resistance and found them all at about 50 Ohms. Must be the o-rings.

I used 5/16" OD, 1/16" material. The post below suggests a 9/32" OD and didn't specify the material size. The original o-rings didn't look damaged and the material diameter was much smaller than 1/16". I first tried just spraying some silicone on the components but that didn't help. As soon as I put the new (slightly larger) o-rings in, the problem was solved. I can control floor, panel/floor and no-floor correctly. Yay!

See the o-ring replacement post here. A lot cheaper than a new EATC.
EATC is Rebuildable

BTW, the EATC passed the self diagnostic even when it had the o-ring failure.