EATC: Getting what you need

Let's face it -- this mod could cost a BUNDLE if you don't do it "right" -- and "right" in this case means mostly junkyard ("JY") parts. We're going to do this mod in the style of the overhead console and just get parts with "pigtails" and splice together our own wiring harnesses. This is WAY simpler than trying to get the full harness out of an Explorer and retrofitting it to our Rangers -- and it takes a lot less time as well.

Blend Door Actuator/Motor

There is ONE part you may wish to consider buying, and it's about $60. It's the blend door actuator (which I sometimes call a servo -- because it is). It's the most "moving" part in the system and the most prone to breakdown. Mine is partly "new", partly not. It's the electronics from an Explorer 1997 EATC actuator, and the gears and motor from a Ranger 2003 manual actuator. The result is a "rebuilt" actuator that should be reliable. We'll see! That's a trick you can use on your own if you have a year Ranger that doesn't have manual cables to control the blend door. 2001 and 2002 DO have cables. Prior years and 2003 and later MOSTLY do not have cables but instead have manual servos -- but count on nothing.

You can get the one for an Explorer from a Ford dealer. Go in and ask for a "blend door actuator for a 2001 Explorer with EATC". When you get the part, open it up and look at it. It should have "EATC" or "ATC" stamped on it. If it has "MAN" stamped on it, don't buy it and make them find the correct one. It will have an additional plastic bracked underneath the actuator and you'll have to remove it. It just "clips" onto the drive unit with split pegs. You can either cut the pegs or compress them and push them through. I usually cut them.

Here's the two parts next to each other. Don't depend on the color of the casing to define it. Notice the unit on the left says "ATC". Get as new a unit as you can find as it presumably has less wear. Very early units had weak gears that stripped easily. The one on the right was the one I took out of a truck I modified for a friend, and I used his old one as the source of the housing and gears for my "hybrid" rebuilt actuator which is working fine. These units are about 3 to 4 inches square, and about an inch thick not counting the drive shaft which protrudes from the bottom.

AGAIN PLEASE NOTE: MAKE SURE YOU GET THE CONNECTOR YOU SEE PLUGGED INTO THE ATC/EATC unit. It resembles the connector used on manual ones, but the wires are on different pins and it won't work without modification -- best to just get the correct one!

Where is the actuator motor? Up under the dash on the passengers side. Open the glove compartment of the donor vehicle and push in the sides of it until it drops down. Looking in, you will see a horizontal black plastic duct, and above it some grey plastic structures and more ducts. In between the duct and upper structures is a gap. The servo is mounted towards the left side, on top of the lower duct, as shown here.

There are typically a total of three 5/16 (or 8 mm) hex-head, self-threading screws. It requires a "cut down" or fairly short socket and a small 1/4" drive ratchet to remove it. First, unplug the connector. Then I take the rear screw out FIRST. The reason for this is so the servo doesn't move when you are getting that back screw out. It's a real pain and if you drop a tool back there, you need a magnetic retriever to get it back. Take your time!

The "approved" procedure for removing/replacing these is to TAKE THE DASH APART!!! That's too much work and though this part is a real pain in the neck, it's worth it for the time saved. Don't forget to GET THE CONNECTOR AND AS MUCH HARNESS AS YOU CAN FROM THE DONOR VEHICLE. 4 to 6 inches of harness is fine -- but if you can get more, fine. You can also see if you can unlace the wrappings all the way back to the EATC head unit if you're getting it from the same vehicle and then you won't have to splice this piece back in later. I usually just cut it, but it's up to you. It's more work in the JY, but less work at install time, or vice versa depending on what you choose to do.

By the way, 1995 through 1997 have SEVEN wires on the connector, and 1998 through 2001 have FIVE. Both of them can be used but get the newer one if possible, or put the gears from a newer manual one in the old EATC one. Either unit will work, though.

One final note on these: ones from the cars generally won't work. They have the connector coming out the TOP of the unit and not the side and there would be no room for that in our trucks.

Fan Speed Controller

These units are also sometimes "iffy" when salvaged due to corrosion. They are close to $100 new though, so salvage is still the best way to go. Later, I'll explain how you can test all your acquired pieces as a system to determine if they will work or not. Basically, you will just hook up all the pieces before you install them.

The unit can be found on the donor vehicle (and will mount on your vehicle) in the engine compartment, just below and to the right of the fan motor as shown. You have to remove the speed control servo to get to this location. It just mounts with one bolt on the top of the fender on the passenger side, then drop it down a bit and pull it out. Unplug the electrical connector, and set it out of the way. What is the speed control servo? If you have cruise control, it's the thing blocking your access to the fan motor area! The fan controller shown here is actually mounted in a Ranger, prior to wiring, but it's the same location in both vehicles.

Just remove the two mounting screws (and keep them) and pull it straight out of the housing. You may find it mounted with torx (T-10) or with more conventional fasteners.

Note which way the heat sink faces (up or down). I've been mounting them heat sink DOWN so the fins don't collect condensation.

The controller shown is "analog" -- that is to say, it has a big transistor that just acts as a resistor to control the fan speed. This means it gets HOT. That's why it mounts on the intake side of the fan and you MUST mount it there. I'm using a cool-running PWM digital speed controller from a Lincoln but that's a more complicated mod if you want to use an Explorer/Mountaineer control head unit. I may cover this mod in the future for those who are interested.

These pictures of the fan controller were generously contributed by Ryan Hooks, whose site is here on CarDomain. He is a fellow experimenter on this mod and offered things from his write up to be used here. This is REAL nice because I was a MORON and forgot to photograph the fan controller! I don't use this type in my truck, so I don't have one to photograph now and the two trucks I've already modifed other than mine are far away! You can see other diagrams and information that may be helpful on his site.

Sensors

There are three sensors you need: interior, exterior, and sun load.

The interior sensor is located in the dash, behind the center panel and to the right. It's clipped in place immediately behind the oval louvered vent to the right of the radio. It just pries away from the inside of the dash -- it's not screwed or glued in or anything. Below are two views of it. Again: GET THE HARNESS.

You may wonder what the white hose is for: well if you read the previous page, it's the "aspirator" that draws air into interior sensor. Get the hose and all fittings that go with it, including any part that goes through the firewall (if present). If you can't get the hose, or it's no good, then 3/4" corrugated plastic "bilge hose" from a hardware store will work.

We'll be hooking it up a bit differently than the Explorer, and it's easier. However the hose needs to reach all the way to the right of the passenger compartment and you may not be able to salvage enough. Generally, it takes two pieces to make it with the white salvaged hose.

The exterior sensor (the "ambient" temperature) is mounted up on the radiator bulkhead in the front of the engine compartment. It may be one of two sensors if the donor vehicle also has on overhead console. The two sensors shown are ones for an overhead console, but represent the design of the sensor you're looking for. The OHC and EATC sensors are virtually identical in appearance except for the wire colors and they are electrically different. The one you want for this mod has wires that are PK/BK (pink with black stripe) and RD/OR (red with orange stripe). GET SOME OF THE HARNESS! Leave about 6" or so of wire on the sensor if you can. No LESS than 2".

The location is up around the drivers side headlight, mounted on the radiator bulkhead. They can be hard to reach. If you are going to do an OHC (overhead console) then also get that sensor while you're at it.

And finally, the sunload sensor is a simple photocell that detects the level of sunlight entering the vehicle. It also mounts using clips and has no screws or other fasteners. The diagram to the left is once again courtesy of Ryan Hooks. Below right you can see where the sensor is located under the top of the dashboard. If you look at your Ranger, at the black part of the top of the dashboard around the defroster vents, you'll see an enigmatic round hole on the passenger side that has no apparent purpose. That hole is for this sensor. Isn't it nice that your Ranger already has a place for it? To get to the area you have to take out the passenger airbag. It is held in with two bolts accesible by dropping the glove compartment.

MORE TO COME -- PAGE BUILDING IN PROGRESS!!!