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I am going to be installing a brake controller this weekend. I need to connect it to the the 12v cold side of the brake lights. I haven't found the wire yet and am starting to become frustrated. Does anyone know where this wire is? Maybe have a picture?

Also, anyone have any helpful tips for running the wires or installing the fuses under the hood? I will be using: Brake Controller 6 and 4 Way Installation Kit, 10 Gauge part # ETBC6 from etrailer.com


Thank you in advance!
 

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Unless you are talking about something else
He is trying to wire a brake control unit for electric trailer brakes, not the lights.

To the OP: I can't give you specific instructions since I have an '07 OB. It is usually pretty easy to locate the brake light switch, since it contacts the brake pedal arm directly. Peel back the harness cover to expose the wires. Probe with a sharp steel object like a needle (a sharpened straight dental pick works excellent), and use your volt meter to find the "switched" side of the brake light switch. Splice your controller wire into that wire, so it will get it's signal to apply current to the trailer brakes.

Now comes the really fun part - stringing wires though the interior and firewall....... that etrailers kit looks complete, but they don't give you a 10 AWG or larger black 12 volt charge wire for the trailer's house battery. You may not need one and you can leave it disconnected for now - but you might in a year or two, and it will be ten times easier if you run the wire now!

And I strongly recommend that you install a separate large gauge ground wire on your trailer through its harness - don't rely on the ball coupler for a return current path!

Here is a good reference page:
http://www.etrailer.com/faq-wiring.aspx

John Davies
Spokane WA USA
 

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You are correct. The kit does not come with the 10 AWG power supply wires. I was thinking of going to Home Depot or Lowes and picking up some wire there. Only difference is that the wire you can purchase from etrailer does not have a ground. The 10/2 wire at Home Depot/Lowes does. Will this matter?

You spoke of a ground wire from the trailer to the battery? Or from the trailer to a grounding point on the vehicle frame?

Have you installed this kit? I am wondering where I should place the fuses for the kit. I haven't looked too much under the hood, I was thinking somewhere around the battery/fuse box.

I think I will eventually install a battery. What will I need to set up now to make the install easier. I am going to install a junction box somewhere. I think this one from Amazon will work.
 

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You are correct. The kit does not come with the 10 AWG power supply wires. I was thinking of going to Home Depot or Lowes and picking up some wire there. Only difference is that the wire you can purchase from etrailer does not have a ground. The 10/2 wire at Home Depot/Lowes does. Will this matter?
WHOAAA! You can NOT use household solid core electrical wire in your car. You must use a multistrand wire! Solid core wire will fracture from vibration. Buy your wire at an auto parts store like NAPA. That eTrailers kit has two stranded wires inside an insulated sheath.

You spoke of a ground wire from the trailer to the battery? Or from the trailer to a grounding point on the vehicle frame?
Both!

Run a big ground wire from the frame of the trailer to the ground terminal on the trailer connector plug. Many trailers don't have this, and you end up with light problems due to a poor ground through the ball and coupler. Bad grounds cause 90% of all trailer lighting problems......

Normally you will also connect the ground pin on your car connector to a good clean steel ground on the chassis. Sand off any paint so bare steel is exposed, then coat the connection with liquid electrical tape to seal it and keep it from corroding.

Have you installed this kit? I am wondering where I should place the fuses for the kit. I haven't looked too much under the hood, I was thinking somewhere around the battery/fuse box.
I haven't used that kit, but it is simply a collection of all the stuff you would normally need, at a reduced price. The relays need to be as close as possible to the battery positive terminal.

I think I will eventually install a battery. What will I need to set up now to make the install easier. I am going to install a junction box somewhere. I think this one from Amazon will work. Amazon.com: Conntek 10000 BX Trailer 6 or 7 Pole Junction Box: Patio, Lawn & Garden
That is a neat little J box. I've never seen that one. I used exposed (stainless) terminal strips from West Marine, and covered the terminals with liquid electrical tape:



That J box would be very fine for bringing all your connections to the trailer harness into one spot, but you should make sure that you can use heavy gauge wires with it. You need a minimum of 10 AWG for the battery, preferably larger, to minimize voltage drop on the long run from the alternator to the trailer battery. If you have too much voltage drop, your battery will never reach a full charge. You could always bypass the J box for the battery charge wire, and run it direct to the battery.

John Davies
Spokane WA USA
 
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