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johnboy2 · 03-28-2016, 09:29 AM

I am wiring my tail lights in my 2013 Terrain. I found a plug and play harness to hook up at the connectors at the tail light assembly and run a 4 wire flat cable to the front of the car. That being said the harness going from the lights to under the car appears to be the same as the existing one for the trailer lighting.

Can anyone think of a reason not to use that existing harness and just plug in at the hitch and run a four wire cable to the front of the car?

BFlinn181 · 03-28-2016, 10:45 AM

When you wire it like that, you'll be powering all the lights on that circuit. Side marker, front, etc. will perhaps pull more power than your RV can handle in the circuits provided. That's why folks use diodes to limit where the power goes.

johnboy2 · 03-28-2016, 01:10 PM

I haven't plugged into the coach yet( I'm to lazy to pull it out of the shed) Using a aux batt. all the lights seam to work fine. I did have to run a wire for each tail light.

I'm still looking for possible pit falls to this scheme. It just seems to easy.

BFlinn181 · 03-28-2016, 02:02 PM

Quote:

Originally Posted by johnboy2

I haven't plugged into the coach yet( I'm to lazy to pull it out of the shed) Using a aux batt. all the lights seam to work fine. I did have to run a wire for each tail light.

I'm still looking for possible pit falls to this scheme. It just seems to easy.

Plug in the lights again at dusk and see if more than the tail lights and rear blinkers light up. A battery can put out more power than the long run from the RV battery through the umbilical.

Cougarkid · 03-28-2016, 03:40 PM

I thought about the same thing when setting up my wrangler for 4-down. Problem is, the braking system in your toad will apply the brakes and turns the brake lights on. The second brake light feed from the RV will reek havoc on your electric system.
That is why people either install additional bulbs in the housing or diodes in the wiring. Diodes allow for 2 powers in but only 1 power out.
Hope that helps some.

johnboy2 · 03-28-2016, 04:03 PM

Now that makes some sense that two sources could cause problems, but really your only paralleling 2 12v sources which is done when jump starting etc.

This kit is available several places which does just what I'm proposing I think although there isn't a wiring diagram I can find

johnboy2 · 03-28-2016, 04:04 PM

forgot the link TrailerMate 780072 2010-2012 Terrain, Equinox Tail Light Wiring Kit for Towed Vehicles | Broadview Parts

pwhittle · 03-28-2016, 04:58 PM

That kit has built-in diodes.

Quote:

Built-in diodes safeguard car's wiring
Won't interfere with electrical system when towed car is not hooked up to RV

Paul

johnboy2 · 03-28-2016, 06:39 PM

I stand corrected.

I really don't understand why the diodes are needed

pwhittle · 03-28-2016, 09:06 PM

The diodes are there to isolate the running light and brake/turn signals originating from the coach and the toad from back feeding to each other. With the diodes, the two signals can independently light the bulbs they are connected to and the signal is not fed back to the other vehicle.

Think of the diodes as check valves in an air system. You could have a single tank with two compressors feeding it. Either one will fill the tank to capacity (like turning on the bulb) but will not feed the pressure to the other compressor.

Paul

WILDEBILL308 · 03-28-2016, 09:16 PM

I just added the Blue Ox led light set to my tail lights. No problems.

Bill

johnboy2 · 03-29-2016, 10:45 AM

I know what diodes do and now think the brake light is the only ckt that would be affected and than only when using the turn signal at the same time as braking

**NLOVNIT** · 07-25-2016, 02:12 PM

I'm resurrecting this thread because I have a question on this backfeeding from the toad wiring thing.

We just had our '14 CRV wired for towing behind our coach so the brake/turn signal lights come on when our Brake Buddy is activated. When the CRV is attached to the coach via the umbilical cord & if we turn on the CRV headlights, the coach running/marker lights come on. Just the running/marker lights - not the head/tail lights.

We didn't have this problem with our previous '06 Jeep, because it had a set of unused sockets in the tail lights & the installer put extra bulbs in those & ran wiring just to those bulbs. That isn't the case with this CRV because there aren't any extra unused sockets for extra bulbs.

Is this a problem? Are there supposed to be diodes (as mentioned in previous posts here) in the CRV brake/turn lights wiring?

Lori-

P.S. Currently we are NOT turning on the CRV headlights & I don't see any reason to while towing.

BFlinn181 · 07-25-2016, 02:22 PM

Since you wouldn't have the toad hooked to the RV with the toad's headlights on, it's really a non-issue. You could go to the expense to install diodes to prevent current from flowing from the toad to the RV, it's a condition you shouldn't encounter in normal circumstances. Diodes also cause a voltage drop when current passes through them in the correct direction, so you'd dim your toad's lights.