# Is the 12V "charge" wire in the 7 pin connector live?



## mkwl (Jan 21, 2005)

I just bought a new Bri-Mar dump trailer. I was told that this unit will "trickle" charge off the truck through the 7 pin connector. My question it- is the 12V "charge" connector on my truck live (have power to it) from the factory or do I need to add something to make it live? I was discussing this with a few guys and there's a little controversy over it.

Thanks,
Matt


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## wild bill (Feb 10, 2007)

*12 vt*

depend on how new ,and if it has any factory wiring or factory plug ,if it's a factory plug it will have a legend on the cover telling what the individual plug do .the center pin is usually the 12 vt accessory pin take a test lite and it should be hot all the time ,if not it may need the correct fuse installed to make the circuit hot .then the next problem is what pin on the trailer plug is the charging wire ,if it has one ,it has to be in the same location or it will not work ,or blow fuses .:waving:


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## Western1 (Dec 4, 2008)

Ditto. If your truck came with the tow package you would have the harness and a fuse for the brake control in the glove box.


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## mkwl (Jan 21, 2005)

Okay- I already have a brake control in the truck (put one in when I bought my other trailer with brakes last spring). So- if the brakes are working (and they are), then the battery on my dump trailer is getting its "trickle" charge?


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## ABES (Jun 10, 2007)

I believe on my truck it is an orange wire that comes from the fuse block all the way to the plug that charges that battery. I may be wrong but I think that battery is only for a breakaway?


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## Mark Oomkes (Dec 10, 2000)

mkwl;771320 said:


> Okay- I already have a brake control in the truck (put one in when I bought my other trailer with brakes last spring). So- if the brakes are working (and they are), then the battery on my dump trailer is getting its "trickle" charge?


No

Do you have a circuit tester and know how to use it?

You could answer this question in much less time if you have one and know what to do with it rather than asking here.


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## lilweeds (Aug 3, 2007)

Now this has been discussed over and over. The wire in the upper right side is the 12v "hot" wire. You need to install the fuse (40amp maxi) in stud "1" in the underhood fuse box.


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## jomama45 (Dec 25, 2008)

As rsvees said, it's a big,red 40 amp fuse in the elec. center under the hood. If you find a red "dummy" plug, there's no accessory power to the trailer plug. Then look under the dash at the brake controller harness. The fuse may still be taped to the wiring harness.


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## Dustball (Dec 5, 2008)

The key should be in the run position when testing for voltage at the 12v position.


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## grandview (Oct 9, 2005)

Even with the trickle charge you need to drive to China for a full charge. Put the charger on at night to keep it full.


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## calhoun (Oct 18, 2003)

mkwl;771284 said:


> I just bought a new Bri-Mar dump trailer. I was told that this unit will "trickle" charge off the truck through the 7 pin connector. My question it- is the 12V "charge" connector on my truck live (have power to it) from the factory or do I need to add something to make it live? I was discussing this with a few guys and there's a little controversy over it.
> 
> Thanks,
> Matt


As others said 12v is wired to the plug if your truck has the tow package. If your truck also has the dual isolated battery option then the plug will be hot. If not you will need to pull the dummy fuse and install a real 40 amp fuse.
I have a dump trailer it is not a trickle it can draw up to the 40 amps and will charge just like your truck battery. You should unplug the trailer when dumping. I sometimes blow the fuse if I operate the dump while connected to the truck. These units will draw about 150 amps when operated. As the battery ages more of the operation power will get taken from the truck.


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## mkwl (Jan 21, 2005)

Okay- well the truck has a 40A female fuse in "stud # 1" in the underhood fuse box. I don't have a voltage tester with me at school- but with the fuse being there, the 12V "charger" at the trailer connection should be hot, right?


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## jomama45 (Dec 25, 2008)

mkwl;771589 said:


> Okay- well the truck has a 40A female fuse in "stud # 1" in the underhood fuse box. I don't have a voltage tester with me at school- but with the fuse being there, the 12V "charger" at the trailer connection should be hot, right?


Yes, you should. But I'm not quite sure what a female fuse means?


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## mkwl (Jan 21, 2005)

Instead of it having prongs coming out of the fuse, the fuse goes onto the prongs in the fuse block.


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## tuney443 (Jun 25, 2006)

A little off-topic, but any trailer in NY running electric brakes needs to have the dedicated or not brake battery charging at all times,whether by trickle,solar,or a monkey turning a gyro{} to be DOT compliant.


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