Recently, I got a 2012 E-150 cargo base model van for work.

I am happy with the factory radio, since it already has an auxilary port where I can plug in external stuff. However, I want to add 2 more speakers, and I prefer to mount them on the partition in the front end.

Tonight, I decided to take the radio out to see if it would support a 4 speaker installation.

What I found was, even though the only 2 speakers installed are the ones in the doors, there is wiring coming out of the harness that connects to the radio, that according to a wiring diagram I found online, go to left rear and right rear speakers, colors match the diagram and all.

My question is, where do these wires go? They feed from the radio into a bundle of wires that is all taped up, and from there I have no idea where they go.

I was thinking maybe they go to the back doors, but the only 2 wires coming into the back door are for the license plate marker, and there are no wires whatsoever coming into the left side back door.

Anyone know where I could find the other end of these wires?


Also, I took an ohm reading of the door speakers. Both read 4.6 ohms. The rear speakers I want to install are 8 ohms. Is it ok to install 8 ohm speakers on this radio?

 

If you had the factory EVTM or wiring diagrams publication it would show the wiring for your speakers leads from the actual radio connector inside the dashboard to a bundle of wiring and other connectors located at the bottom of the left/drivers side B-pillar. They tend to be covered by the trim covering the seat belt inertia reel.

Because your van wasn't factory equipped with the 6 speaker option wiring leading to the side and rear doors isn't present. Since you're HVAC running wires through the various body cavities shouldn't be a huge challenge.

If you're not familiar with or motivated to build your own rear speaker harness from factory-type connectors and terminals I'd simply follow the schematic to the connector at the lt side B-pillar, tap into the appropriate wire and run lines to the doors etc.

Honestly having extra speakers without a bit of sound insulation doesn't add a lot of great sound, IMHO anyway---BTDT.

HTH

 

If you want to add a bit more punch to the stereo, you can feed those rear speaker wires directly into a modestly powered amp (about 200 watts or less) that has speaker level inputs. You will need a solid 12v line to the amp, possibly remote shutoff (unless it has autoswitching) and of course, speakers that will match and handle the new amp.

You can also buy a speaker level adapter to feed any standard amp that only has line-level inputs. (this is not a great solution, but it works)

And yes, you can use 8 ohm speakers with a 4 ohm amp or radio...but the speakers will not be driven to the full output the amplifier is capable of.

Going the other way, using 4 ohm speakers with an amp thats expecting 8 ohms can cause early distortion/clipping and/or overheating and failure of the amp and destruction of the speakers.

BTW, a simple ohm reading across the speaker gives an approximate value, and helps determine shorts or opens, but that DC resistance value is not the same as it is when being fed with audio frequency AC (impedance changes with the applied signal). For all we know, those speakers could be 4 ohms, 6 ohms, or 8 ohms. Even a printed marking can be erroneous.

You will possibly need two more items: A ground loop isolator and a power line noise filter.

Keep in mind that JWA is correct...the bare metal innards of a cargo van are not the best acoustical situation you can have...but it depends on your particular tolerance for marginal Hi-Fi.

Let us know how it turns out.

 

So I went out tonight and took off all the trimming and found the bundle of wires. Come to find out, the other end of the 2 rear speaker wires terminates into a harness that is under the steering wheel. But get this.

The stock radio, even though wires are coming out of it for rear speakers, does not support a 4 speaker installation. The radio has pins coming out of it where the 4 rear speaker wires would hook up, but when I hooked the speakers to it, they did not work. So, for grins, I disconnected the front speaker wires and low and behold, my new speakers worked when I hooked them up to the front connections.

What I ended up doing was wiring the speakers in series with the stock ones, one on each side. I found out MY speakers are also 4 ohms. So, in series they equal 8 ohms now.

Rather then mounting them in the doors, where as mentioned there is no insulation, I mounted them on the partition that separates the front end from the back. So far, they sound good, will give it the ultimate test tomorrow.

 

I believe this is actually a factory programed setting in the radio....its possible the Ford dealers can change that parameter but I dont know that for a fact.