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After reading about a particular new car without Homelink, I got the idea that I could replace my rear view mirror with a more functional one. The original one also had some weird unsightly deterioration behind the glass near the edges, so this seemed like a worthwhile mod that I could manage.
I. Background; goals of the project; the mirror.
II. Wiring.
III. Hiding the new wiring.
IV. Gotchas and final thoughts.
V. Photos.
I. I hoped to replace my original, non-functional rear view mirror with a replacement with built-in Homelink and compass. I didn’t want to spend a lot, since this project wasn’t really that critical.
In this writeup, I omit some details, especially ones that are so generic that they are obvious, and ones so specific that they are unhelpful to mention.
For photos needing additional explanation, I provide that separately at the end.
I bought the mirror used on ebay for about $40. There are literally hundreds of mirrors on all different sites at a wide range of prices. No magic about how I chose the one I did. It arrived looking like it was brand new. Your mileage may vary, obviously. It came with a wiring harness, that plugs into the mirror, and with bare wires at the other end that you have to connect (Photo #3).
The mirror has a “standard mount,” which is different from the original Ford mount. I viewed some Youtube videos to see how to remove the old mirror. It would not have been self-evident, but after seeing the videos, it wasn’t that hard. Fortunately, the “button” mounted to the windshield holds the new mount just fine. I was not sure that would be the case. The new mirror’s mount has a set screw that easily tightens to the button with the proper Torx driver (Photos #1, #2).
II. I decided I wanted the compass to operate only when the truck is on, and the Homelink to be powered all the time. That last part is controversial. Some advise against this. But all my previous Homelink equipped vehicles worked this way, and it’s been fine for me.
The included harness has three wires (Photo #3). One for the compass, one for the Homelink, and one for ground. I had to do some research online to find this out, and to determine which was which, and upon doing so I could then confirm that the wiring into the harness was correct.
At the other end, I needed to provide appropriate power to these wires. I purchased something called “Add-a-Circuit” (Photo #4). These are easily found online and/or at auto parts stores, and are relatively inexpensive.
The way they work is they plug into an existing fuse location. You remove the fuse, plug this device into the same slot, place the fuse you removed into the device so that everything on that circuit works as before, then add a second fuse into the device for the new thing you want to power. Finally, the crimp end connects to what you are powering. (This is a logical description of the functioning, and not an ordered list of steps to make the actual connections. I trust all who do this to make their own decisions about how best to work safely with electrical components on cars.)
Photo #5 shows the interior fusebox in the passenger side footwell. The trim is removed.
Photo #6 highlights the grounding location, and the two slots I chose to replace with the Add-a-Circuit devices. (Radio circuit for Compass; Interior lights/horn for Homelink.) The circuits and fuse locations were found in my Owner’s manual.
Photo #7 shows the completed wiring.
III. To hide the wiring as best I could, I routed it up beside the passenger door jamb, up the pillar, and across the top of the headliner. Photo #8 shows the area in question before I did it (some trim removed). The hardest part (perhaps the only hard part) was getting the wires from the fuse box area out toward the door jamb. The area where I chose to do this is shown in Photo #9. Photo #10 shows the end result. Photo #11 shows some of the wiring up the pillar. I did not want to remove the trim on the pillar. To fit the wires in there I put them through a plastic drinking straw wrapped with black electrical tape, then pushed the straw into the opening between the pillar and the windshield. The headliner was easier; there’s tons of room to shove anything in there.
Photo #12 shows the completed result, while #13 shows the wiring behind the mirror a little more clearly. I am considering buying a wire cover (Photo #14). I’ll decide that later.
IV. The Add-a-Circuits make an “L” shape coming out of the slot once installed. This means they cover (obscure the view of) adjacent fuses, as the “L” extends out over the top of at least one nearby fuse. In some slots, the Add-a-Circuit might not fit at all.
In one of the two I used, I was forced to place the Add-a-Circuit in only one direction into the slot. It is the opposite direction of the other one. Some product information I read online suggested that the Add-a-Circuits have to be inserted in a particular direction. I don’t know when or why (or if) this is true, but in my case, it looks as though that isn’t true.
Be aware, there are at least three standard sizes for car fuses, and I mean different form factors, not the amperages of the fuses, and the Add-a-Circuits are sold in different sizes to match the fuse sizes. Neither the fuses nor the Add-a-Circuits are interchangeable across different fuse sizes, so make sure you know which type of fuse your vehicle uses before purchasing or doing anything related to changing or swapping (or simply replacing) fuses.
Though I don’t show it clearly, I took great care to label all wires at all points, to avoid any mixups when connecting anything to anything.
This mirror came with no instructions for setting up Homelink nor calibrating the compass, but that information was easily found online.
Finally, my biggest goof. The mirror I bought was manufactured at a time, or for a model year, whose Homelink isn’t compatible with my relatively new garage opener. I’ve now learned that for it to work, I have to buy a special device which, once installed in my garage, will allow an old Homelink device to work with a newer opener. I found one on ebay for about 30. I assume everything will work fine once it arrives.
V. Photo descriptions.
1. new mirror, mounted on existing button, prior to adding any wiring.
2. same, with better view of mount.
3. wiring harness/pigtail included with mirror. Plain black tubing also was included.
4. Add-a-Circuits.
5. passenger footwell area where fuse box is located. Power was drawn from here.
6. same, with relevant fuse and ground locations highlighted with white circles.
7. same, after wiring completed. Note that the Add-a-Circuits, from this angle, look like small, solid black rectangles, and they block the view of adjacent areas. Note also that the red wiring attached to the Add-a-Circuits loops around. This creates a bit of an optical illusion in this photo, so you have to look closely to see what is going where.
8. door jamb area where wiring must go.
9. red rectangle shows a bolt I loosened to run the wires behind. This was the only easily accessible passthru between the fusebox and the door jamb area. Note the piece of black tape I used to protect the wires once I retightened the bolt.
10. wires are hidden next to door jamb. Near the top of the photo, next to the vent, you can see some of the wires, but they are hidden pretty deep, and visible only with the door open, and barely even then.
11. wires between pillar and windshield. The white area closer to the bottom is the wires, exposed between two sections of plastic straw covered with black tape. This photo is taken parallel to the windshield, looking along the inside of the windshield back toward the pillar.
12. finished!
13. same, with wiring showing (inside black tubing).
14. wire cover to protect/hide wires shown in Photo #13, not yet purchased.
I bought a Homelink bridge/repeater on ebay for about 30. It was easier to install than I thought, and works better and more reliably than I expected. All good.
I bought the wire cover pictured above new on Amazon for 10.
So, old, plain, non-functional mirror out. New mirror, with homelink and compass, wired and good to go, in.
