Hooking up power from tow to harness to power trailer battery

[SherrillR]

Hello, my trailer is 7 pin and my car is 4 pin. There are extra leads which I was told one of them is to hook car battery up to charge trailer battery. Does anyone have or know where to get instructions on how to do this ?

 

[TheBar]

The 7 pin could accept power, but your car 4 pin has only a ground wire with no positive power. The other 3 pins are left turn signal, right turn signal, and tail lights.

 

[Rob&Deryl]

What trailer and what car?
The 7 pin to me indicates the trailer has electric brakes which says something about its weight.

 

[SherrillR]

1974 Prowler weight is 2800
2006 Toyota Highlander is tow vehicle.
the supply store said something about running wire from extra wires on harness to car battery to charge trailer battery? Is it just to positive thermal ? Which color wire on harness ? There is purple, white, blue and brown left over from the 4 pin

 

[Rene T]

We would really like to help you but it’s obvious you have no background in RV and car electricity. If I were you, I would take my car to the nearest U Haul place that installs hitches and talk to them. Like it was said earlier, it sounds like you have electric brakes and if that’s the case, you would need a brake controller installed unless the tow vehicle has one built in. U Haul can explain all of that to you.

 

[SpencerPJ]

Often times cars / trucks that have 7 pin also have a heavy duty alternator to handle charging the car and trailer battery, if the power wire is active. As mentioned above, I suggest you have a uHaul or hitch shop evaluate. I agree, if the trailer has a 7 pin, it probably has brakes, and for a reason. No worries, just an extra $100 brake controller needed, and a wise upgrade for a marginal tow weight any way. Good luck, safe travels.

 

[TheBar]

My 2008 popup has a 7 pin connector from the factory and has no brakes. The 7 pin connector is becoming pretty standard.

 

[LarsMac]

I second Rene T .
Looks like the work of a "Do-it-yourselfer" and unless you can talk to the guy that did it, You will save yourself a lot of headaches if you just take it to a UHaul shop, or some other shop that knows what they are doing.
The learning curve on this will be rather painful if you try do figure it out for yourself.
I was an electrician in the navy, and I would take this to UHaul.

 

[Ray-IN]

Like LarsMac said take it to U-haul, the experts. Todays autos can have as many as 37 computers in each one.

 

[SherrillR]

We would really like to help you but it’s obvious you have no background in RV and car electricity. If I were you, I would take my car to the nearest U Haul place that installs hitches and talk to them. Like it was said earlier, it sounds like you have electric brakes and if that’s the case, you would need a brake controller installed unless the tow vehicle has one built in. U Haul can explain all of that to you.

Thank you have an appointment with them

 

[SherrillR]

Like LarsMac said take it to U-haul, the experts. Todays autos can have as many as 37 computers in each one.

Thank you made an appointment

 

[Rene T]

Thank you made an appointment

Please let us know how you make out. Good luck.