12volt tie in help please

[VoodooBlue_Vixen]

I need to tie into a 12v source at the back of my 5th Gen 4R for a backup camera. I opted to mount it inside the cab next to my rear dash cam. But I need help finding a 12V source & ground in the cargo area. Any ideas? Electrical work is truly my weakest link.

 

[RDub]

If it doesn’t draw much current can you tap into the source and ground that feeds your rear view dash camera? I may be misunderstanding what you mean by rear dash camera.

 

[VoodooBlue_Vixen]

If it doesn’t draw much current can you tap into the source and ground that feeds your rear view dash camera? I may be misunderstanding what you mean by rear dash camera.

I'm afraid to do that, as it's an independent cable that ties into the dash cam itself. Its a Rove brand dash cam, with front, rear, & interior cameras recording while the car is on. It's great for trail cam footage, traffic issues, or an accident.

 

[Jacket]

Electrical work is truly my weakest link.

But your nail polish game is strong!!

The wiring that feeds into the hatch is a PITA to deal with, so I'd rule that out unless desperate. Is there a 12V plug anywhere in the cargo area? Or trailer wiring? Or maybe wiring to a (useless) OEM inverter?

Will you also need to splice into the reverse wire to trigger the camera? That's usually up front in one of the kick panels.

 

[VoodooBlue_Vixen]

But your nail polish game is strong!!

Haha! Thx!

The wiring that feeds into the hatch is a PITA to deal with, so I'd rule that out unless desperate. Is there a 12V plug anywhere in the cargo area? Or trailer wiring? Or maybe wiring to a (useless) OEM inverter?

There is a plug, it's on the far right side & it's the OEM one that only turns on with a button. My trailer wiring is screwed up & doesn't work. Another project I need to figure out, but it's daunting. What about a tail light???

Will you also need to splice into the reverse wire to trigger the camera? That's usually up front in one of the kick panels.

I will not. Luckily that is part of the stereo harness. So it already triggers when reverse is actuated.

 

[jeffcon]

@VoodooBlue_Vixen the 12volt socket in the back of mine always has power next to the inverter/120v outlet right? My inverter requires the front dash switch to turn on, but the 12volt socket for mine has always been live at least.

If you did the tail/running lights, then yeah? Mine is older so if I want running lights on, I have to manually do it (no DRL), but I almost always turn them on manually anyways.

When I hook up my RV I have rear camera that runs off the running lights there and works well.

The wires are super easy to tap into imo for the tail lights once you get in there.

 

[Jacket]

What about a tail light???

Not my favorite choice but definitely an option and it’s right there.

 

[nakman]

If you used a tail light, then the camera only gets power when the light is on. Not sure what is what you want here... in fact what do you want- switched on with the accessory, or always hot?

My suggestion is run a wire all the way from the battery- 12-14ga would be plenty big enough. Add in line fuse close to the battery on the + side,, negative side to the fender where the battery ground is also connected. Then down along the frame probably right along the fuel line... zip tied all nice and happy. For extra credit you can put it inside split loom.. then you've got an always hot wire back there, if you need to disconnect the power you know right where the fuse is, and if you want it to be switched on with accy you can add a simple relay under the hood, tapping one of the other fuses for the positive trigger.

 

[Inukshuk]

We need more information:
Constant 12v or ignition switched?
Ignition switched 12v so the camera is only on when the truck is on, unless the camera has a "on trigger", perhaps from the head unit.
Light circuits in newer CANBUS systems often monitor current for bulb-out fault codes, so a tail or DRL circuit may or may not work.
If constant, check for constant at a dome light or run to the battery. If from battery, 14 or 16 ga probably plenty for that camera. Larger is never bad, just more difficult to run. Fuse it at the battery,
If ignition switched, probably from something at the fuse box that powers a 12v outlet

 

[VoodooBlue_Vixen]

We need more information:
Constant 12v or ignition switched?
Ignition switched 12v so the camera is only on when the truck is on, unless the camera has a "on trigger", perhaps from the head unit.
Light circuits in newer CANBUS systems often monitor current for bulb-out fault codes, so a tail or DRL circuit may or may not work.
If constant, check for constant at a dome light or run to the battery. If from battery, 14 or 16 ga probably plenty for that camera. Larger is never bad, just more difficult to run. Fuse it at the battery,
If ignition switched, probably from something at the fuse box that powers a 12v outlet

Ignition switched would be better, those little cameras can't handle constant power I've read. I don't need a trigger, as that is in the head unit. A dome light tie in would be from the center of the second row, and I'd have to fish it through the headliner.
The rear cargo area lights are in the lift gate & bringing power back from that would be a mofo. I'm going to check the power outlet back there to see if it has constant ignition power. But not today, it's cold outside.

 

[Inukshuk]

Ignition switched would be better, those little cameras can't handle constant power I've read. I don't need a trigger, as that is in the head unit. A dome light tie in would be from the center of the second row, and I'd have to fish it through the headliner.
The rear cargo area lights are in the lift gate & bringing power back from that would be a mofo. I'm going to check the power outlet back there to see if it has constant ignition power. But not today, it's cold outside.

Electrically speaking ""those little cameras can't handle constant power" is illogical. An electronic device might be on for 8 hours while driving. That's functionally equivalent to constant. Anyway, lets set that issue aside a minute.

"I don't need a trigger, as that is in the head unit." This makes sense and is a clue to how your system works. The way a trigger *might* work is to "activate" (via a switch of sorts built into the camera) the constant 12v to the camera such that the camera is connected to constant 12v but not "on" or drawing any current until the head unit triggers it. In such a configuration you could supply ignition switched or constant 12v to the camera. The head unit "trigger" is the "switch." Aftermarket radio amps function in this fashion. Due to an amp's high current draw a big fat wire runs 12v from battery to amp and a tiny wire from head unit "triggers" it on.
Caveat to an ignition switched power source if the manual calls for a constant 12v source: Camera is a very low current draw but you do not want it drawing when the truck is parked and off - except for the ability of the camera to turn on from motion (many cams have this "activate when parked" feature).

If you know ignition switched is proper, don't bother with the dome light constant.
Is the power outlet 12V or 120V power outlet? Likely both are ignition switched. Manufacturers generally protect consumers from themselves by not offering constant power accessory outlets. Its too easy to drain a battery from one. A 120v outlet might have BOTH constant 12v to the inverter and an ignition switched source to activate the inverter, providing both for your needs in a convenient location.

 

[Inukshuk]

PS. Camera and head unit owner's manual will provide the answers as to what type and how many power sources you need.
PPS. You can ground to any body metal.
PPPS: Do you have a voltmeter? Its essential for this work and need not be complex or expensive.

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