URGENT: Tail light wiring harness - Which wire under power for backup?

[Okki]

Does anyone know by chance what wire on the tail light assembly is under power when the backup light is on? I think it may be the red wire, but I can't figure it out based on the electrical schematic that I have and I don't have anyone handy to put the truck in reverse while I measure with a multi meter....

I want to use that wire to splice into in order to trigger the relay that will power the 12V auxiliary backup camera. Need to get everything wrapped up tonight since I'm a support vehicle for an SCCA team tomorrow.

This is the connector where I'm looking to pick up a "hot when in reverse" wire.

THANKS!
Okki

EDIT:
Not specific to the location at the rear tail light, but this does seem to support it's red:
http://www.toyota-4runner.org/5th-gen-t4rs/190943-wiring-cheat-sheet-2014-w-o-smart-key.html

 

[96r50]

I don't have the wiring diagrams handy or I'd check for you. If you chock the wheels, put the parking brake on and put the truck in reverse with the engine off it should still light up the reverse lights.

Or, some guys will tap into the reverse wire in the 7 pin trailer outlet instead of getting the signal inside the truck.

 

[Okki]

Or, some guys will tap into the reverse wire in the 7 pin trailer outlet instead of getting the signal inside the truck.

Already short on space to run more wires into the taillight housing. So not really an option to tap into the trailer harness. I did find a thread providing that option and detailing the wires here:
http://www.toyota-4runner.org/5th-g...r5-factory-bumper-rigid-sr-q.html#post2253405

Okki

 

[barryhiram]

Does anyone know by chance what wire on the tail light assembly is under power when the backup light is on? I think it may be the red wire, but I can't figure it out based on the electrical schematic that I have and I don't have anyone handy to put the truck in reverse while I measure with a multi meter....

I want to use that wire to splice into in order to trigger the relay that will power the 12V auxiliary backup camera. Need to get everything wrapped up tonight since I'm a support vehicle for an SCCA team tomorrow.

This is the connector where I'm looking to pick up a "hot when in reverse" wire.

THANKS!
Okki

EDIT:
Not specific to the location at the rear tail light, but this does seem to support it's red:
http://www.toyota-4runner.org/5th-gen-t4rs/190943-wiring-cheat-sheet-2014-w-o-smart-key.html

Should be red wire. But like [MENTION=105875]96r50[/MENTION] stated.............

"chock the wheels, put the parking brake on and put the truck in reverse with the engine off it should still light up the reverse lights." to confirm

 

[Okki]

Hooked up my multi-meter on the driver side. Balanced it on top of my fire extinguisher so I could see it from the driver seat.

It showed 12 volt (before the multi-meter fell down), so I hooked the relay switch pole and connected to the power and ground of the camera. The wires that it received power and ground from before I taped off (just in case I need to go back to them).

When I put the truck in reverse, the head unit did not switch to the camera (it did when I used the wires that were spliced into the factory wiring in the roof.).

The video signal is still going to the same place in the roof factory harness.

Anyone any suggestions on what's keeping the head unit from switching to the video source? Tomorrow I'll have to confirm that the power-out from the relay is hot when in reverse.

Okki

 

[flyinhawaiian01]

could be many things, but the ones I'd check first are these:

Is the red wire +12VDC or -12VDC? Could be a negative switched wire, not positive.

Are you feeding + or - to the relay? Depends how you wired the relay into your vehicle, as you can have either as a trigger for the relay (is there a reason you even need a relay? If its +12VDC coming out of the reverse light switch, there's really no need unless your camera is pulling a ton of current! Most don't even pull half an amp)

Do you have constant power and ground set up on your relay? Those both need to be live when your cam/stereo is running.

Is your stereo capable of switching the trigger type, ie., + or - trigger? Some stereos have a setting in the menu to match the polarity of your vehicle's switch.


So, other than these, are you able to manually get the camera to turn on from the menu on your stereo? You'll still need to be in reverse since that's what you're using to power the camera, but maybe you can manually "view" the rearview cam to determine that its actually working. If you can, then you can eliminate the wiring for the most part and search for the menu to switch polarity.

If not, then I'd start testing power at the camera, then check the feed to the stereo for video input.

Edit: forgot to add, here's a reference for a '12 wiring, seems to be +12 at the red wire, and you can also pick that wire up under the dash instead of in the rear if you want it closer to the front. IIRC, 2F is the same connector that Antman (and I) used for his foglight rewire mod.

 

[Okki]

Uhmmmm, not sure on the +12VDC or -12VDC. Since my measurement setup was location challenged, I just looked at the big numbers for a 12. I'll have to check that out tomorrow.

The relay has constant power and ground off my aux fuse panel.

I used a relay, because I read where lots of modern vehicles use power modulation to tail and headlights, which can result in aftermarket backup cameras not functioning correctly.

My head unit is the stock (pre-entune) Toyota head unit with factory cam and nav. I don't recall seeing a camera setting or mode switch anywhere on it. Any idea where in the menu it might be?

Thanks! Okki

 

[rigtec]

"Does anyone know by chance what wire on the tail light assembly is under power when the backup light is on? I think it may be the red wire, but I can't figure it out based on the electrical schematic that I have and I don't have anyone handy to put the truck in reverse while I measure with a multi meter...."

Hey Okki,

RED wire is back-up lamp (HOT) and WHITE/BLK is GND (you can ignore the pen marks on this sheet, that was for someone else I just got finished with about ten minutes ago!):



Rgds!

 

[flyinhawaiian01]

My head unit is the stock (pre-entune) Toyota head unit with factory cam and nav. I don't recall seeing a camera setting or mode switch anywhere on it. Any idea where in the menu it might be?

Thanks! Okki

Sorry man, I'm not familiar with the stock unit, thought you were using an aftermarket stereo head!

With your relay, are you able to hear it "click" when you put it in gear? That there will tell you whether its getting the correct signal without even testing it with the multimeter.

At this point, I'd just put the parking brake on (assuming your garage/driveway is flat and not on a 5º+ incline!) and with engine off, just shift into reverse, get out, check power/ground and +/-, then get in, pop into neutral or park and check again to make sure you have all the info from your wires.

Once you get clicking from relay as you shift in and out of reverse, its all a matter of video signal getting back to the head unit. Of course, this is where I will leave it up to others that have more experience with the video signal input of the stock unit, as I have none in this department!

Good luck and report back with what you find!

 

[Okki]

Sorry man, I'm not familiar with the stock unit, thought you were using an aftermarket stereo head!

With your relay, are you able to hear it "click" when you put it in gear? That there will tell you whether its getting the correct signal without even testing it with the multimeter.

At this point, I'd just put the parking brake on (assuming your garage/driveway is flat and not on a 5º+ incline!) and with engine off, just shift into reverse, get out, check power/ground and +/-, then get in, pop into neutral or park and check again to make sure you have all the info from your wires.

Once you get clicking from relay as you shift in and out of reverse, its all a matter of video signal getting back to the head unit. Of course, this is where I will leave it up to others that have more experience with the video signal input of the stock unit, as I have none in this department!

Good luck and report back with what you find!

First relay may have been bad. Second one is giving me 12v in reverse as wanted. Head unit is NOT switching to the backup video as expected.

Have a wiring harness on the way from installer.com to hook right into the back of the head unit instead of splicing into the factory wiring.

Dropping it off to get the factory wiring repaired tomorrow and after that it will be dropped off at an automotive audio/video shop to fix the backup camera issue. At least I have a clean power source ready for them.

Although I am curious why I'm not getting video in reverse when everything is the same aside from where it's getting power from!?!? [MENTION=83083]rigtec[/MENTION] any ideas or suggestions?

Okki

 

[rigtec]

First relay may have been bad. Second one is giving me 12v in reverse as wanted. Head unit is NOT switching to the backup video as expected.

Have a wiring harness on the way from installer.com to hook right into the back of the head unit instead of splicing into the factory wiring.

Dropping it off to get the factory wiring repaired tomorrow and after that it will be dropped off at an automotive audio/video shop to fix the backup camera issue. At least I have a clean power source ready for them.

Although I am curious why I'm not getting video in reverse when everything is the same aside from where it's getting power from!?!?

Okki

Hi Okki,

I just looked at the electrical plot for the back-up cam. Do you have TWO HOT lines running to the camera from your monitor (rear view mirror or Navi screen)? The scheme shows CV+ CV- B+ plus the grounded shielded coaxial cable going directly to the camera from the monitor (mirror). Just curious! If you need to see it let me know and I'll post the rear view camera diagram! Best

 

[rigtec]

Here's what I've got @Okki:



See the rear view cam on the right: CV+ CV- CB+ CGND... all four lines go straight to the mirror; 2011 limited.

 

[rigtec]

Oh...

Plus they've got a HOT line from IG (ECU fuse 10A), and the power source from the gear shift (REV safety Switch) to the REV in the monitor.

 

[Okki]

I wonder if the system is expecting something on the ground wire coming from the camera?!?

I started at the second (non factory) camera and followed the power and ground back (red RCA plug). I disconnected those inside the truck and hooked them up to the new power source.

The wiring harness to the factory cam has been interrupted (that's what's being fixed on Tuesday), so the secondary camera is what was providing the picture to the head unit over the past couple of weeks.

Considering that that's the only change, it must play a role in this.

Thanks for the assistance [MENTION=83083]rigtec[/MENTION] and [MENTION=118444]flyinhawaiian01[/MENTION]!

I'll post more here as I learn more in the coming week or two.
Okki

 

[CargoDave]

Backup cam on RV

I want to run my backup camera on my 16' RV to be on when I'm towing it. I have the cam wiring already up front and going into my junction box where my 7 pin harness wires are located. Can I use the 'red' +12v hot pin on the 4Runner 7 pin male plug for this ( 1'oclock position )? Will the +12v power supply be on only when the vehicle is running, as I imagine it would?