Separate 12 Volt systems

[Ralf]

I am thinking about wiring my tail lights, turn signals,runing lights and licence plate light off the 4 prong flat connector on my F150. It also has 7pin connector. Then I will use on board battery for my interior lights and 12 volt outlets, perhaps with welding cable from truck battery to heavy duty 12 volt connector at the tongue ( the kind I've seen used to connect Warn Winches on Jeeps) for charging house battery. This will keep my running lights simple and not involve the on board 12 volt system.

From other posts it seems I need battery isolating device to keep house battery from draining truck battery. I saw one called Hellroaring Battery Isolator.

I'm looking to plug and go with my running lights without worry about my house 12 volt system. Also I can camp as soon as running lights are installed. Any drawbacks, concerns or suggestions?

[Dale M.]

Why would you NOT want to use 7 pin.... It has all lamp functions plus backup light (bet you never considered that on trailer) and has +12 volt lead for battery charging. I don't know about Ford, by my Chevvy is fuses at 40 amp and disconnects when truck ignition is turned off. Excellent for charging "house" battery on the road....

Seems to me you are trying to invent something that is already there.....

Dale

[bobhenry]

I think we are discussing isolation of the interior lights and other loads from the tow vehicle and I fully agree.

I started out to be able to run EVERYTHING from the tow vehicles battery and soon found the error of my ways. An internal short in the stranded power cord I was using without the protection of a fuse enlightened me real quick. I agree , let the tow vehicle run just the towing lights and charge an onboard battery. Downstreem from that battery a breaker/fuse 1st and then distribute the loads as needed thru seperate fuse protected circuits. There is something real unnerving about watching the wiring smoke and change colors before your eyes.

We have all been pretty much in agreement that after a weekend of camping no one wants to find out that the tow vehicle has a dead battery.

Dale is right why not utilize the 7 way the way it was designed. If you have an alternate tow vehicle that is not equipted with a 7 way you can leave the 4 way tapped in and use it as a feed when necessary you just won't be recharging your onboard battery

[bravebear]

I have an 2005 Chevy. I added a 7 wire adapter to the factory trailer wire harness. I have lights but no 12 volts. I was told that I needed to inatall a fuse but can't find a blank space for one. Does any one know
how to get the 12 volts to work.

[jeep_bluetj]

1. Use the 7 pin. The 7 and 4 are connected together inside your truck. The running lights are always seperate from the house power.

2. If it's a factory 7 pin, ford has the +12 lead (to charge the house battery) fused and disconnects when the key is off. Factory ford truck trailer wiring also has seperate running light circuits from the main truck ones. Totally cool, so if you blow a fuse for the trailer lights, the truck lights still work. DAMHIK.

3. Wire it (almost) exactly as shown at http://www.accessconnect.com/trailer_wiring_diagram.htm. I'd add a 30A self-resetting CB to the 12V charge line.


If the +12 line is NOT switched with the key, pull out the connector when you get to a campsite.

I'd not put in an isolator or a diode. Too much fuss for not much gain.

[jeep_bluetj]

I have an 2005 Chevy. I added a 7 wire adapter to the factory trailer wire harness. I have lights but no 12 volts. I was told that I needed to inatall a fuse but can't find a blank space for one. Does any one know
how to get the 12 volts to work.

Google yeilded http://www.toyhaulermagazine.com/forum/ ... wtopic=567

But I'm sure your owner's manual also says which fuse it is too.

[Dale M.]

I have an 2005 Chevy. I added a 7 wire adapter to the factory trailer wire harness. I have lights but no 12 volts. I was told that I needed to inatall a fuse but can't find a blank space for one. Does any one know
how to get the 12 volts to work.

Fuse should have come taped to your "brake controller harness" for electric brakes( I think mine did) .... FUSE BLOCK is located under hood, over left front fender..... Its a fuse pretty much at front corner of fuse block near battery and towards center of engine compartment... Its labeled "STUD #1*"... Or something similar and probably has a red dummy plug in that position...

THINK owner's manual also gives some information on how to locate it....

Dale

[bravebear]

Thanks much for the help.
I found a dummy fuse in the box under the hood.

[Ralf]

Thanks all, 7 pin it will be.