I thought some of you might like to see how I installed the power system for my 12V accessories. Currently I have a GPS and XM MyFi Radio. I will also be adding a two-way radio and rechargeable flashlight.

My power is being fed from the trailer brake control port above the foot brake. If you are not going to use a powered brake, this is an excellent source of power because you can get up to 30 amps of power. I used the cable that was included with the truck to build my harness. You’re not going to easily find too many more places this easy to get 30 amps of free power.

From there I went into a 12V relay to switch the power off and on with the ignition. To power the relay I tapped into the switched power source for the radio. It is the light green wire with the yellow stripe.

From the relay I terminated the power into the Rig Runner from West Mountain Radio. This allows me to easily add more 12V devices without a lot of wiring. Each individual port is fused to protect the electrical system and isolate each component. The ends have Anderson Power Pole connections so you can easily remove them and plug them into other sources.

I have posted pictures and a schematic to my gallery if anyone wants to see what I have done. (https://www.f150online.com/galleries...w.cfm?num=9259)

Tony Fischer
Germantown, TN


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FULL GALLERY (https://www.f150online.com/galleries...w.cfm?num=9259)

 

Thats NICE

 

Excellent write-up!

 

Very nice write up, Thanks for sharing.

 

The only problem I see here is that XM sucks when compared to Sirius

Good write-up man!

 

i did the same thing with my trailer brake harness but removed all the pins/wires except pos & gnd

 

Very cleaver to pick up power from the trailer brake controller, it's a great idea. I only don't like wire taps because I'm so uncoordinated I can't get both wires in at the same time in tight spaces. I was dumbstruck when I discovered T-taps. They let me do one thing at a time.

Thanks for sharing.

 

How many amps is comin outta the 12 volt wire you took from behind the radio? Just curious why you even have the positive lead from the the trailer brake runnin to the relay, or the ground even if you went behind the dash for the 12 volt, there wasnt a ground there too? I mean if you took the power from behind the dash you might as well took the ground from there too, or ran the whole thing from the trailer brake. Which id a prolly done, just ran the trailer brake leads into a switch and then into the RGunner thing where youd have 12v at the flick of a switch runnin to all them ports.

 

I may not be 100% positive but I am sure what he is saying is that the 12v source he took from the radio is what triggers the relay to activate his 30A circuit.

FYI

That way when the key is turned on, the power that energizes the radio will energize the coil in the relay closing the circuit and energizes the accessory circuit, and his radio comes to life and so will all of his accessories. If he turns the key off, the power to the relay coil is no longer there, and the circuit is opened and his accessory circuit turns off too.

 

Correct, the whole purpose of the relay is to switch the power off and on. The amount of current used to switch the relay could be measured in milliamps. But from the trailer brake I get a full 30 amps of power which will come in handy when I add a 100W two-way radio and/or an inventer. If I had pulled all the power from the radio I could have probably only got a few amps of power for all my gear.

I didnt want to have to flick a switch - I really like that it comes off and on with the ignition. Think of a relay as a switch that is triggered when it has power applied. $3.50 at AutoZone.

Tony

 

Thank you! Thank you! Thank you! I was contemplating the same thing to hard wire a TomTom GPS and I really apprecite the very detailed work here & in your gallery. AWESOME!


And now for my future searches:

switched gps through power brake

 

You need to do the math, 12v at 30amp is only 360 watts!
you need to add upc the loads, by the time you add all your accessorys and a 100watt amp and a invertor, you may overload the 30a circuit. This is without considering voltage drop also. For as much work as you did you could of just run a seperate circuit to the battery with the correct size wire and fuse for your load , this way you avoid mistakes and promlems messing with the factory wiring. It is best to avoid messing with the factory wiring, it will only cause warrenty issues when your PCM blows up or something burns.

 

No worries. I have that all calculated. I would not run both at the same time anyway. Even if I did, I have the primary fuse in the RigRunner at 25 amps so I would blow a fuse before I caused an electrical problem. There is also a 30A fuse on the brake control. In addition, the rig runner has individiual fuses for each device with appropriate sized fuses. Some of the devices have their own fuses in their power supplies as well. That means I could have up to 4 fuses in-line for each device. Overkill - yes, but well protected.

The radio I have only uses a few amps except when transmitting. Even if I did I am looking at:

GPS - < 1A
XM - < 2A
Inverter (150w) - 12.5A
Radio (@ 100w) - 8.3A

I am at ~ 23.8A assuming each device is pulling maximum draw all at the same time.

I have run directly to the battery before in other vehicles and I found this much easier and better protected. As far as I am concerned the less I have to take through the firewall the better. The shorter the length the wire I have to run the better.

 

I honestly don't know what I'd do. With all the negative feeling going around about dealerships trying to void your warranty, It is a bit scary for me to touch any damn thing. I really have to admire you people who don't even care and just spend the money altering your trucks in a 1000 different ways.

But This looks like a simple solution, and easy enough to dissconnect if there were to be a problem or any issues. And I really do like that Rig Runner thing, although at about 40 bucks it is a bit pricey for me.

I think what you did looks great and will probably work great without any issue, I just don't know what route I will take myself, Probably the same one - Its easy, the power is there... so why not.

 

Man up and git 'r done!! Your warranty is safe. The 30A brake circuit is the easiest way to add powered accessories to the F150! It's isolated/fused and Ford gives you a pigtail to tie into it. I used it on my off-road lights and it couldn't be any more straight forward to wire up!!!