My trailer has surge brakes so I need to tap into the reverse light circuit to convert the 4 wire trailer harness to 5 wire. Just wondering if anyone knows if the reverse light wiring runs in the lower cargo area anywhere...trying to avoid having to trace it from the hatch into the headliner. Thanks!

 

If my memory serves me right, the reverse lights wire run under the cargo area floor where it meets the side wall on drivers side. The wire was red in my 2008. I know it's on the drivers side, I just don't remember if it runs on the floor or a couple of inches up the side. Either way you need to remove the floor

 

if you remove the left most cubby hole / bin in the trunk area (not a quick process). you will see a female connector. that is the connector the dealer uses to install their trailer package. one of those wires will be a reverse wire.

i tapped into all of those wires when i added a 4 pin harness

 

Thanks for the replies. I'm working on the project right now. I've got the rear cargo floor compartments out and the tailgate lower covers off.

In the tailgate the reverse light wires are pink with a gray hash mark. There are no wires under the cargo floor with the same color scheme. Does anyone know if the harness from the tailgate runs through the headliner to the front of the car vs. coming down the C-pillar?

I'd rather tap into the circuit in the front footwell kick pannel than try to run a wire from the inside the tailgate down into the cargo hold...

Thanks!

 

The 4 wires in the factory trailer harness are: ground, running lights, left turn/brake, right turn/brake.

 

Thank You!!

The reverse trigger wire was a reddish/magenta color, in the fat harness on the left side of the cargo area.

Now to figure out which wire in there feeds the 12v power outlet...

 

Multimeter...best tool ever.

 

In the fat harness, mine has multiple red/magenta wires. How do you know which one to use?

Thanks

 

If memory serves me right, it's this red one I took a picture of:



For reference, that's the fuel door manual release handle to the upper left. Of note, I am using this wire only to trigger a relay, not wiring it directly to the trailer harness. I do not know what reserve, if any, amperage is available on this red wire. I am running power to the relay from the rear 12v outlet.

While I was in there, I also added a pair of these:





Now we can see what's on the ground behind the car when backing up at night!

 

Thank you!! All hooked up!

 

WOW. Great idea. factory back-up lights are useless at night.

 

Thanks for this post. It saved me a lot of time finding the wire. For my 06 RX400h my wire was gray. Must be a hybrid thing.

I went for the OEM look. I fished the 5 new wires through the existing OEM loom and spliced the inside connector on the new wires. I then bolted the 5 wire plug to the horizontal plate that was welded to the hitch. The connector is slightly farther under the bumper now so it is hidden better.

 

Hi all,
This thread and photo was very helpful. I just did this to my 2008 RX400h - it was exactly the same red color (magenta/red) as the photo above. It was buried inside the bundle and had to be dug out. Note that the wire is a medium gauge (thickness) compared to the different wires in the bundle. There are both very thin and quite thick wires in the bundle but the one that is clearly a step up from the thinnest wires is the backup light.

 

I know this is an old topic but this thread helped me with my auxiliary reverse light installation. Just wanted to confirm that for my 2006 RX400h (USA market, Japanese made) the wire was GRAY, not red. It is the thickest of the gray wires (there are multiple). I don't know exactly what gauge it was but it was between the lowest and highest of that wire bundle in the photo above. I think it might be able to handle an extra light by itself as long as the original reverse lamps have been replaced with LED's, but I used this gray wire to trigger a relay and took main power by tapping in to the 12v outlet. The outlet can be pulled out without removing the whole side panel and there is plenty of space to add a quick splice connector and push the wire through behind the 12v outlet to the left and down with the other wire bundle closer to the rear.