1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

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

Discussion in 'Chevy Trucks' started by mkwl, Mar 18, 2009.

  1. mkwl

    mkwl 2000 Club Member
    Messages: 2,362

    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.

  2. wild bill

    wild bill PlowSite.com Addict
    Messages: 1,239

    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:
  3. Western1

    Western1 Senior Member
    from MI.
    Messages: 752

    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.
  4. mkwl

    mkwl 2000 Club Member
    Messages: 2,362

    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?
  5. ABES

    ABES PlowSite.com Addict
    from MN
    Messages: 1,322

    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?
  6. Mark Oomkes

    Mark Oomkes PlowSite Fanatic
    Messages: 13,253


    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.
  7. lilweeds

    lilweeds PlowSite.com Addict
    Messages: 1,178

    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.
  8. jomama45

    jomama45 PlowSite.com Addict
    Messages: 1,190

    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.
  9. Dustball

    Dustball Senior Member
    Messages: 274

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

    grandview PlowSite Fanatic
    Messages: 14,609

    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.
  11. calhoun

    calhoun Senior Member
    Messages: 165

    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.
  12. mkwl

    mkwl 2000 Club Member
    Messages: 2,362

    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?
  13. jomama45

    jomama45 PlowSite.com Addict
    Messages: 1,190

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

    mkwl 2000 Club Member
    Messages: 2,362

    Instead of it having prongs coming out of the fuse, the fuse goes onto the prongs in the fuse block.
  15. tuney443

    tuney443 PlowSite.com Addict
    Messages: 1,847

    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{:D} to be DOT compliant.