Eric vs. the Blend Door

About 10 days ago I was heading down to my Tue/Thu night ride in my truck. It was about 75 degrees out, so I turned down the heat on my Ranger, but it didn’t work – I was stuck on hot, which is pretty darn hot. I had to go on Max AC to get it tolerable.

After a bit of research, I found that the problem was likely to be the mix door. Ford uses a potentiometer to detect the position of the dial in the dash, and then a microcontroller sends the door to the proper position. It’s a fairly elegant design, except that the code self-detects the limits of the door by moving the door and sensing that it slows down. That would be fine, except that the shaft on the door is plastic, and it’s not up to the torque of the actuator, so it breaks. And then, if you want to fix it, you have to pull the whole dash apart to get to it.

This is so common that there are companies that specialize in aftermarket replacements. I bought mine from HeaterTreater.net, and put it in yesterday. It’s a very elegant hack. You take out the actuator, cut the bottom out of the duct with a dremel, vandalize the door so it will come out, and clean out all the shavings. The new door fits in and then you pull a pin so that the spring-loaded shaft seats in the pivot, put the actuator back on, verify that things work, and then close things up with some foil tape.

It would be easy to do if the part of the duct you have to cut wasn’t facing down right up to the firewall. As it was, I had to fall back on my car stereo installation skilz and lie backwards on the seat with my head under the dash.

About 2 hours later, it was done.


So, what do you think ?