After a lot of hemming and hawing I dropped about $1600 at Crutchfield.com and bought a Kenwood DNX7140 stereo for Big Bertha. The unit is double-DIN, but the F250 takes a 1.5 DIN radio. The opening in the dash is large enough, but the opening in the dash cover is a bit smaller. Just a bit of work with a Dremel and the unit slides right in. Since I had to consult several websites to see how this would work, I figured I’d do my own write-up for anyone attempting something similar. The install took me about 8 hours, but I spent at least 4 of those hours puzzling over the location of the wire to tap into for engaging the backup camera. Details below…
- new stereo (mine is a Kenwood DNX7140)
- backup camera (Kenwood CMOS-200)
- iPod connection cable (P.I.E. KNW/USB-AV2 USB A/V iPod Cable)
- Ford F250 wiring harness adapter
- Factory radio removal tool
- 4″ zip ties
- 8″ zip ties
Step 1: Turn on your existing stereo and remove any CDs or cassettes that might be living in there. Once you disconnect the old stereo it will be much more difficult to get them out.
Step 2: Park your truck in a shady spot.
Step 3: Make connections from the new stereo’s wiring harness to the Ford adapter. It’s a lot easier to do this on your workbench then inside the dash. Here’s the wiring harness diagram and the finished product.
There are two wires on the harness for the stereo’s lighting. The orange wire is labeled “illumination” and the orange/black wire is labeled “dimmer.” The DNX7140 doesn’t dim in the sense that as you roll the rheostat next to the headlight switch the display gets brighter or dimmer. Instead the unit has a “bright” and a “nearly as bright” setting. When I hooked up the system I didn’t know that so I connected the orange/black “dimmer” wire to the harness on the stereo. Bzzzt, wrong answer. The wire you want to use is the orange “illumination” wire. When the stereo senses 12 volts on this wire, it assumes the dash lights are on and goes into “nearly as bright” mode. The stereo itself has 4 dimmer settings configurable in the software: none, dim, sync, and nav sync. Setting the stereo to “none” means it will never dim at all. “Dim” means it’s dimmed all the time. “Sync” means it dims when it senses 12V on the illumination wire. Lastly, “nav sync” ignores the illumination wire input and instead dims the display when the GPS unit thinks it should dark outside, based on your current location and time of day. Fair warning: this unit is pretty bright even when “dimmed.”
Step 4: Disconnect the truck’s negative battery cable (unless you want to listen to the door chime for the next few hours).
Step 5: Crutchfield sent me a pair of radio removal tools free with my purchase, but you can make your own from a wire clothes hanger if you need to. Just insert them into the holes on either side of the unit and gently pry outwards while pulling. If you find yourself prying hard, you’re not aligned with the internal tabs properly. The unit should slide right out with just a bit of coaxing.
Step 6: Disconnect the antenna wire and the existing wiring harness from the back of the stereo.
Step 7: Remove the dash cover. There are two 7mm screws accessible at the top of the stereo opening after you have the stereo out. These are the only two screws holding on the dash cover. The rest of the cover is held in place with clips. Start at one side of the dash and gently pry it off. Work your way around until the whole thing is free. I had to engage the parking brake, turn the ignition to the on position, and shift into 1st gear to get the cover over the steering column. Once you have the cover loose you’ll want to disconnect the wiring harnesses to the headlight switch and dimmer controls (there are two red tabs that need to be slid out to release the harnesses), the 4wd switch harness, the power point harness, and the accelerometer for the airbag. Toss the dash cover into the back seat, shift back into Park, and turn off the ignition key.
Step 8: Enlarge the dash cover opening. The DNX7140 is nearly identical in depth to the stock stereo, so that’s not a problem. The height is bit more though, so a slight modification is required on the dash cover. The opening inside the dash is plenty tall enough for a double-DIN stereo.
The plastic lips at the top and bottom of the dash cover are all that prevent the new stereo from sliding in. The lips on the sides can be left alone. I used a Dremel with a sanding drum and spent about 5 minutes grinding the lips flush with the rest of the dash cover opening.
Step 9: Run the wiring for the back-up camera. I mostly wanted the camera to make it a lot easier to hook up to my trailer. Being able to see the ball on the back of the truck relative to the hitch on the trailer makes this a one-man job without having to get out and look constantly. You don’t want to hard mount the camera until you can test out its position on the display, but you should still run the wiring back and just leave the camera dangling for the time being. Start at the back and pull the wire along the left side frame rail until you get under the cab. I punched a small hole in the parking brake cable grommet with a screwdriver and fed the wire though. The wiring harness itself was a bit large to push through here without making a big hole, so I removed the pins from the connector, pushed them through the grommet, and then reinserted them into the connector. In case you push the pins out before writing this down, the pin orientation from the underside of the connector is red, yellow, empty, and black.
Pull the wire under the floor carpeting and up through the stereo opening, then plug it into the back of the stereo. Don’t push the grommet back in place yet, as you’ll need to run another wire through it in a bit…
Step 10: The fuse for the stereo is number 8. I attached the red wire for the camera here since it will never be in use unless the stereo is powered up anyway. The ground for the camera can be attached under the dash in the same place as some other grounds.
Step 11: The camera includes a reverse sensing wire. Ignore it. The reverse sensing wire you want to connect is the long one from the back of the stereo. This wire caused me the most frustration because, although I could find the right harness under the dash, it’s always powered until it gets back to the relay box under the hood. So, poke that wire back through the floor grommet and snake it up under the master cylinder. Next to the fuse box there’s a relay for the trailer harness.
Splice into the reverse wire in this junction box and you’re set.
Step 12: At this point you can reconnect the battery, turn on the backup camera and aim it. Once you’re happy with the view, permanently mount the camera and zip tie all of your under-truck wiring in place. Also push your floor grommet back in place.
Step 13: Mount the microphone for the phone system. I just glued it to the A-pillar on the driver’s side, but after using the system I think I’ll move it just under the rear-view mirror. It’ll be the same distance from the driver and much closer to the passenger.
Step 14: I mounted the GPS antennae on the dash at the lower left corner of the windshield. It seems to work just fine there.
Step 15: Wrap up all your wiring, reconnect the radio antennae, and push the stereo into its opening in the dash. It’s a tight fit with all the wires, but a little wiggling will get everything neatly packed away. To connect the stereo to the dash I drilled a few holes in the cowl on either side of the stereo opening and then ran a few 5mm bolts through into its housing. Seems to hold it nicely in place.
Step 16: Now’s a good time to reconnect the battery for good, power up the unit, and make sure everything works to your satisfacation. If so, reinstall the dash cover and its wiring harnesses, clean up your mess, crank up some tunes, and drink a few beers.