Hello all,
I have a question for the wiring experts. I have an 07 F150 FX4 with the 7-Pin OEM factory trailer tow connector. From what I can tell, it appears to have all the wiring I need for wiring up the interior lighting and the Third Brake light that will be coming with my new SnugTop XV camper shell I'm ordering soon. The 7-Pin trailer tow connector appears to have a backup/reverse wire connection, a 12 Volt connection, and a electrical brake connection that should work for the third brake light. I do know that there is also a CHMSL (Center High Mounted Stop Lamp - fancy acronym for third brake light) light-green wire (not connected to anything) somewhere in the rear of the truck wire harness for the third brake light too, but if I can get everything from the 7-Pin trailer tow, that will be much easier. I don't use the 7-Pin trailer tow connector for anything, and could make a plug for wiring the SnugTop to it, and still be able to remove the plug if I ever do tow anything with the 7-Pin. Does anyone know if this will work? According to this link: http://www.marksrv.com/wiring.htm, all the wiring appears to be 14 gauge or thicker. And does anyone know if the Pin 4 Black wire 10 Gauge Battery + wire, which I was thinking to use for the interior dome lamps of the SnugTop XV, is constant hot at all times, or just when the truck is keyed on?

I want to know all this because the wiring done by the Gem Top dealer 10 years ago on my last purchased camper shell was strung poorly.

Thanks in Advance,
JSB

 

I could be wrong but I don't think it is hot at all times, according to my trailer brake kit papers the hot is only on with the key on.

 

Not sure where this is at, the closest splice seems to be S333, which is in the left hand kick panel. This is prior to the wire that runs to the CHMSL on the cab of the truck per the diagrams. There is a lead from this splice, but the end location is not noted. Maybe start looking at the left side kick panel, by where the parking brake is at, as a starting point ?

Note sure where that wiring diagram came from on the URL you provided. Maybe that is what the trailer color code is ??
On your truck pin 4 is shown as the right turn signal, and is Dark Green




Power is on pin 5, and is a Orange wire on the truck. This is the 30 A fuse from the battery change relay on the truck, and is only hot in the start / run position ( circuit 964 energizes the coil on the battery charge relay ) as shown on EVTM 95-2.

The pin outs from the Ford Trailer Tow directions :




Hope this helps, let us know if you have questions on any of this, and we'll try to clarify / add to the answers.

 

Thanks SSCULLY and J2H1, for those answers. So would the electric brakes connector on the 7-Pin OEM Trailer Tow connector not work for a third brake light because it would pulse the LED third brake light, as in pulsing the electric brakes? And if I don't have an in-cab electric brake controller, that pin/wire isn't connected to anything anyway?

Thanks,
JSB

 

Without the controller installed, the pin is dead.

I want to say depending on the amount of braking, the amount of voltage on the pin changes, but that is a SWAG, I am not an E-brake controller expert, just taking a stab at how electric brakes might work ( amount of voltage to the amount of caliper / drum closing ?? ).

Take a look in the kick panel, and see if you can find the CHMSL lead that Ford gives you for such items as a cap. They do this do, so you don't have to tap the BOO switch anymore.

Good luck.

 

Thanks again, SSCULLY. I'll just go ahead and use the aftermarket CHMSL you mention and is listed in my Ford Wiring diagrams. I read somewhere (here: http://www.fordf150.net/howto/wire3rdlight.php) that light-green wire is near the back of the truck somewhere not too far from the rear-end on NBS Ford F150 2004+ MY's.

Also, do you have a suggestions for the Key-off/always-hot connection for the camper shell two incandescent lights, without having to run a wire all the way to the engine compartment?

Do you think a Ford decorative LED hitch cover along with the LED third brake light and maybe an LED tailgate light bar might be too much amperage for the light-green CHMSL wire? I know that LED's draw much less power, so I would think that I would be okay. I would wire all these connections in parallel, and not serial. I feel better getting second opinions before I hack into pristine factory wiring.
Thanks,
JSB

 

That is what you are stuck with, if you want alway hot leads. Just get some 14/3 SO cord from Home Depot or the likes, and run it along the frame rail, you into the engine compartment. Dirt easy to do, and gets you what you want, with 2 additional wires for later ( backup lights controlled in the cab ? )

If you are removing the bulb from the truck's CHMSL and adding 3 LEDS you should be good to go. Almost a net zero with that swap.
My 52 LED Truck-lite backup LEDs ( the single lamp DOT version ) draws 1 A each.


The lights in the cap window are the 60 Series STT lights, 4" oval STT, and those are on the truck's STT circuit.
This is from my 2001 setup.
I have the B/U LEDs on my '06, and I have 400 series ones to put in my cap now ( rapid pulse 3 flash then constant on ).
I have a 700 series one on the back of my ZG-1000, replacing the 2 bulb factory stop / tail lamp. Very bright, and gets quite a bit of attention to the cages behind me.
http://www.pbase.com/elvin315/image/41409459

 

The best way to wire a canopy is NOT attach anything to your trailer wiring!! The CHMSL wire on 2004-08 F150s is located on the driver's side frame under the front door. If you look under the truck at this location there is a plastic shroud around factory wiring/plugs, on the outside of the frame. At the front portion of the wiring there is the light green CHMSL wire wrapped onto the cluster of wires. I have wired canopies for the last 15 years and have had zero problems with wiring this way. Run 12V and CHMSL and ground wires through hole in stakehole pocket on the driver side in box. Ground to body behind taillight and run 12V and CHMSL up frame along OEM wiring. Attach CHMSL wire located as above. Then carry 12V wire up into engine compartment and across the cowling and attach to the auxillary post on the battery, preferrably with a fuse link. Good Luck!!

 

Thank You, Topperman, for that info. I ordered my SnugTop XV yesterday, and got $400.00 off the price due to the Portland International Auto Show, and was told by the retailer that the CHMSL light-green wire is actually at the rear wiring harness at the rear section of the truck, drivers side. Is that not correct? And I agree with you. They will need to run at least a 12V wire all the way forward to the engine compartment and fused for the topper's inside 2 incandescent lights. What gauge would be best for two incandescent 12V lights? 14 or 12 gauge?

I am going to have a Recon White Lightning tailgate light bar installed at the same time. I have purchased a Hoppy 40185 T-Connector to flat four (http://www.trailerwiring.com/cgi-bin...cgi?part=40185) to prevent splicing into taillight wiring, and have bought a White Night 7 Pin Plug-N-Go wiring adapter (http://www.whitenight.com/0004149.htm) to get the 12v hot, ground, and reverse from the 7-pin trailer tow connector when the key is on. Since the 7-pin trailer tow connector only has 12v when the key is on, can't do that to light the SnugTop's internal two 12v lights. But at least with all of this, I'm preventing any factory wiring splices. I know it might sound as if I'm going to alot of extra trouble and expense, but to not have the installer hack into the factory wiring, it's worth it to me.
JSB

 

Hey JSB.

1. Unless US built trucks are different, 2003 was the last year the CHMSL wire was located at to rear near the spare tire. All 2004+ F150s I've wired have the CHMSL wire located as prior post.
2. We usually use 16ga. wire for 12v interiors lights, even two. Used 15A blade fuse and will have more than enough juice to run 2 lights and be bright inside.
3. Does your truck have both 7blade OEM plug and 4pin OEM plug? If you do not use the 4pin connector for a trailer you can plug into it for your Recon taillight bar. Definitely best choice not to splice into any factory trailer wiring though!!
Topperman

 

All good info. Thanks everyone. I feel informed enough now about my new truck's wiring and soon-to-be installed SnugTop canopy and Recon White Lightning LED Light bar to be sure that it is wired right. I'm thinking that the CHMSL wire must be up under the driver's side door. I can't imagine them locating it differently between the Ford factories in the US vs. Canada. I'll look for it.

This is a great site, with skilled and knowledgeable members.
JSB

 

One more question for you electrical geniuses. So I installed the Hella F-150 LED Tail Light and 3rd brake light kit a few months ago. That kit has you change out the Number F2 fuse from the OEM 20 amp fuse to the Hella supplied 7.5 amp fuse. I can understand why they do that, but here is my question. I am adding the Hoppy 40185 flat-four (http://www.trailerwiring.com/cgi-bin...cgi?part=40185) adapter to direct-connect to my Recon White Lightning light bar, with the additional needed reverse and 12v leads for the light bar coming from this: http://www.whitenight.com/0004149.htm. So all of this additional LED stuff, including the CHMSL connection of the truck topper's 3rd brake light and a little novelty LED Ford Trailer Hitch cover light, and any trailer connections later, may need more than the Hella's supplied 7.5 amp fuse, don't you think? I know all this stuff is LED, so maybe the 7.5 is fine. As I said before, the original OEM fuse was a 20 amp for the OEM tail lamps that were incandescent based for the brake/turn lighting circuit.

On another separate circuit, I am going to run a separate 10 AWG gauge wire from the engine compartment back to the topper's wiring connections for the two inside incandescent lights and a three-jack 12v cigarette lighter receptacle unit option I decided to add on with the purchase of the SnugTop XV canopy. I'll fuse this separate circuit with a 15-20 amp or so rated fuse to protect the circuit.

Any suggestions about the 7.5 amp fuse for the additional LED loads? Or the other 10 AWG gauge lighting/accessory power tap circuit?
Thanks,
JSB