Flat towing 2013 Auto Focus

I installed bulbs in trail light easy and cheap. Go to the Blue Ox web site download install instructions for base plate,they include instructions for installing light bulb. Ran wiring under car. E trailer has a video on installing lights on 2012 Focus.Link

You will need 4 diodes total. One for each tail light and one for each brake light. This is how you hook it up:

http://i.imgur.com/Gc4pRwQ.png

The reason for the three connections on the specialty diodes is to make it easier to hook up. Bear in mind that those specialty diodes are $10+ each ($40 total) and Radio Shack sells 3 amp rectifiers for $1.35 a pair.

You could use another diode per connection to keep the car's voltage from going back up the trailer harness when you are driving like this:

http://i.imgur.com/w9YwNlY.png

I just cap off the connector that's under my hood. Oh, and if you run the harness up under the car on the passenger side, there's an existing cable run that you can fish the harness alongside and then go into the drain hole just forward of the muffler. You'll have to cut a slit in the plug to pass the harness through.

RK

rjkfsm wrote:


Remember to use diodes.

Wouldn't you need 2 diodes ? 1 to block the voltage going back into the vehicle harness when the towing vehicle is powering the lights and 1 to block voltage going back thru the new wiring you added to the towed vehicle. I assumed that was why the diode blocks sold for this purpose are a 3 lug design.

Thanx for the info.

There are two green/purple wires going to the light assembly connector. One is for the tail light (lower half) and the other is for the brake (upper half). Why they used the same color code, I don't know. I turned on the tail lights and cut one of them to figure out which was which.

Remember to use diodes. The lights are controlled by the vehicle computer and they don't like to have electricity going the wrong way into them. A diode acts like a check valve; it only allows electricity to flow in one direction. To put a diode in, it is best quality to solder and heat shrink, but using butt splice connectors is easier. One end of the diode will have a ring on it. That end gets connected towards the lamp. Before hooking up the trailer wiring, test the diodes' polarity by trying out the lights. If one doesn't work, the polarity is backwards.

Here's a picture. The 2nd one from the top is called a rectifier diode and it's the type you want.

RK

rjkfsm wrote:
I wired my flat four trailer connector into factory light harness using diodes from Radio Shack ($1.35 a pair) to keep from powering the electrical system with my blinkers.

RK

Where exactly did you tie into the Focus light harness? Thanx

You could run a power wire from the towing vehicle and power the brake unit off of that.

The problem with leaving the power on is that it messes up the computer. You will get all kinds of lights. Just doing a battery connected short test tow with my Focus around the parking lot to test the tow bar out resulted in an ABS failure, a Hill Assist failure and a Check Engine Light for a transmission code. I had to pay the dealership to clear the codes. I was also told by the dealer that leaving the battery connected will cause the odometer to track the towed miles. Additionally, leaving the power on will likely result in a dead battery.

I don't use a brake unit and I disconnect the positive terminal. I wired my flat four trailer connector into factory light harness using diodes from Radio Shack ($1.35 a pair) to keep from powering the electrical system with my blinkers. I have towed my Focus from South Carolina to California to Washington to Virginia and have not had a single problem. I've even had a deer cause me to jack the brakes and I had no problem stopping. I know that what I am doing is not conventional, but it works safely and legally.

RK

The battery cable was disconnected at the battery post. The Even Brake unit has two wires, one a positive that is connected to a power socket that is wired direct to the RV and the second is plugged into the receiver on the dash that is also wired into the power from the RV hook up. When the Even Brake negative (ground) lead is connected to the chassis ground, the Even Brake is not powered...however when the negative lead is attached to the negative post on the battery, the Even Brake powers up...as well as the cars computer, and systems. My question is: Does the Tranny pump also come on when that happens? If it doesn't then the problem is solved. If it does then what's the solution?

Where are you disconnecting the battery? Hope it's not on the firewall, as that does not disconnect the battery.

jim