Automatic Headlights Install on a 2010 Ford Fusion SE
I was inspired by this post and I thank them for pioneering this whole idea. However, I found it too difficult to read and all the valuable information is spread here and there. It is difficult for a non-technical car person like myself to read. Below is my guide of how I figured this all out. I explain everything I did and give you all the knowledge I learned to complete this task. This is all in greater detail and without any assumptions that you know anything. I present you with the information you need to know at the time you need to know it and no sooner.
Shopping List:
I bought everything from Amazon.com
Motorcraft SW-6659 Headlamp Switch
Genuine Ford DG9Z-13A018-A Impact Sensor (It's the sun load sensor; not sure why they call it an impact sensor.
Motorcraft WPT1013 Wire Assembly
16-Gauge Red Primary Wire
Tools I used:
Large Screwdriver for prying off car panels and bezels
Electric Rotary Tool for cutting a hole in the defroster vent bezel to hold the sun load sensor
Wire strippers
Wire cutters
Electrical Tape
Coat hanger straightened out. This is for guiding the wires from the top of the dashboard through the back of the dashboard and to the smart junction box.
Flashlight (my eyes needed them to read better)
Heat gun to melt heat shrink tube that comes in the wire harness kit.
After getting all the needed parts and tools, now we can begin.
Installing the headlamp switch.
Follow the steps below as well as look at the pictures for lots of detail.
On the driver's side, there is a panel on the left side of the dashboard. Pull this off. The pictures below show how the panel is attached so you can get an idea of where are the connections.
Look inside the dashboard and see the back of the headlight switch. Press in the 3 tabs along the edge of the switch and the dashboard to release it.
Disconnect the old headlight switch.
Used the same plug and attach it to the new headlight switch.
Push the new headlight switch through the hole in the dashboard until it clicks.
Re-attach the side panel.
Done.
How does the switch work?
You should be familiar with the Off, Parking Lights, Headlights On and Fog Lamp On/Off parts of the switch because those existed on your old switch. There is a new position on the switch for the automatic headlight setting. It looks like a light bulb wit an "A" in the middle.
Without a sun load sensor attached to your car, leaving the switch in the automatic setting makes your headlights stay on whenever you turn on the car. This is similar to when day time running lights are on. From here, you can be happy living without worrying if your lights are on at night because they will always be on while you are driving.
Continue if you want to install the sun load sensor. This will turn off the headlights when there is enough light outside. There is no programming to modify with the sun load sensor. All of the programming is already built into your car.
Installing the sun load sensor.
Follow the steps below as well as look at the pictures for lots of detail.
Locate the smart junction box under the dashboard on the driver's side. You should push the driver's seat as far out of the way as possible because you will be crawling under here.
Push in the tab and pull down the handle to release the 52 pin connector. Make note of how to plug the connector back into the smart junction box.
In my picture, we want the gray side of the connector. Pull on the tab that locks it down and then slide the whole connector away. The picture indicates where we will be putting in a wire in a place named Pin 46.
Using the 16-gauge wire, strip off about 1 inch.
Separate the wires into a small bundle of about 10 wires. These we will keep.
Cut off the remaining wires. This is because the place for Pin 46 is small.
Twist the small bundle of wires into one tight wrap.
Insert this into the slot for Pin 46. In my picture, there is enough wire to go all the way through the slot.
Slide the gray connector back into the 52 pin connector.
Secure all the wires with electrical tape to prevent movement.
Cut off the other end of the wire at about 4 feet.
Prepare a second wire just like this one for the ground starting at step 4 above through 7. You can skip steps 5 and 6.
Remove the defroster vent bezel from the dashboard. I used a large screw drive, stuck into into the grill on one end and pushed down. You can use the pictures for reference to learn where the connections are made.
Use a rotary tool to make a hole in the center of the bezel. You can kind of see an outline of where the hole should be if you look underneath the bezel.
Be careful not to remove too much material. Take your time. Test the size of the hole often using the sun load sensor.
I placed the sun load sensor with the wire side on the driver's side of the car.
Attach the wire harness to the sun load sensor.
I chose one outside wire to be for ground.
I chose one inside wire to be for Pin 46.
It literally does not matter which of the 4 wires you choose so do not spend too much time thinking about this. This is one piece of crucial information that you will not find anywhere else.
Using the straightened coat hanger, stick one end through the center of the defroster vent hole. Stay close to the hood side of the car. The gap is small and hard to find. If you go the wrong way, you will be heading down the vent. You want to head down behind the vent and towards to bottom left of the car.
If you did it right, you'll find the end of the coat hanger somewhere near the smart junction box or brake pedal.
Attach the unused end of the wire for Pin 46 to this coat hanger.
Attach the unused end of the ground wire to the coat hanger also. The end that you stripped will stay near the smart junction box.
Pull the coat hanger with the attached wires gently through the dashboard and back out the defroster vent.
Attach the wire for Pin 46 to the wire harness of the sun load sensor. Remember, I chose to use one of the middle wires of the harness for this purpose.
Attach the wire for the ground of the sun load sensor. Remember, I chose to use one of the outside wires of the harness for this purpose.
Secure these wires with heat shrink tube from the wire harness kit or electrical tape.
Now is a good time to test the system.
Put the headlights in the automatic position.
Turn on your car.
If the sun load sensor is in sunlight, your headlights should be off.
If the sun load sensor is covered by darkness such as by a box or your hands, your headlights should be on.
Be sure to wait about 10 to 20 seconds for the headlights to react to changes in light. It's not going to be instant nor is it adjustable. The behavior is based on the default set by the factory.
Pull the wires back through the hole just enough so you can re-attach the defroster vent bezel. Hide the wires as best you can.
Next to the smart junction box, there is a piece of metal. Attach the ground wire here.
If you have a bunch of loose wires, try to secure them as best you can by wrapping them around things or taping them up.
Done.
Now, you should test your automatic headlights again. Just to be safe, you might want to check all your other car electrical functions as well such as the radio, horn, wipers, etc. to make sure you didn't break anything.
Enjoy!
Here's a video of my 2010 Ford Fusion SE that I took when I first bought it in August 2010.