I have a backup video Camera mounted on my bumber next to my license plate. At night, when my lights are on, there is a light next to the lic. plate which is also on. So at night, when I put my F150 in reverse, the backup camera comes on, but I can't see half the video screen because the lic. plate light is shinning too much into the camera lens. I can not move the camera, because it's in a perfect spot (visual wise).

So my questiuon is, how can I make the lic. plate lights go OFF, when the camera is on? The camera has a 12v wire going to it, and obviosuly the lic. light is a 12v light. So what I need a device/circuit that cuts one 12v leed off, when another 12v leed is on. Kindof the opposite of a relay. Is there a relay that works this way?

Thanks in advance.

 

While you could do it with a relay, in every state of the union it is unlawful to do. Sounds stupid, but if a cop sees that light go out, even just while you are backing up in a parking lot, you will get a hefty ticket.

If you did that mod, you could turn off your license number anytime you were doing something unlawful, thus the laws prohibiting it.

You could use a different bulb in the light, either something a fraction dimmer, or a slightly different color, something that doesn't wash your CCD camera out as much. You could also pull the bulb and paint/color a section of it to cast less light towords the camera.
Chris

 

Understood. However, there is a light on the other side of the plate lighting it just fine. The light on the other side does not bother the camera at all. I tried taping (as temporary test) off the light in different ways, didn't work. I even tried building a small shield around the light to cast a shadow on the light, that didn't work, and lastly I tried building a small hood around the camera, even that didn't help.

But if I disconnect that one bulb, works perfect, and the lic. plate is still lit nicely. I would leave it that way all the time, but it kinda looks ugly (non-symetrical). Hence, I need a relay....

Somebody said to try a two pole normally closed relay.

 

http://www.crutchfield.com/S-t7lRyOs...ech/kb326.html

Everything you ever wanted to know about using relays.
You would be using a positive signal to break a connection.
Since the relay and wires would be under the rear of the bumper you would need to weather seal them.

It would still be unlawful as the law usually states that you may not make any modification that dims, hides, etc. the license plate, even a reasonable common sense mod like you are contemplating.

Would you get a ticket? Maybe. If a cop saw one of the plate lights 'blink' when you activated the back up lights he would probably assume you just needed some repairs and give you a fix-it ticket.

Truck might even pass safety inspection (if you live somewhere that does those) unless they checked the license plate light at the same time as the backup lights.
Probably not a big risk overall.
Chris

adding

Where I mounted my camera, no glare.

 

Chris,
Thanks for the link, great stuff in there.

As for getting a ticket for having a "dim lic plate light", no worries. I'm in NY, I'd be lucky to find a cop that knows we need a lic. plate on the truck in the place!!

You can shoot people in NY and not get a ticket!!

 

Not even going to go the route about trying to tel you what your state laws are, as I don't know NY.
IL, it is like a $55.00 parking type ticket for an equipment violation..no points on your lic...BFD ??

If the camera +12V lead is only on, when the truck is put into reverse, then you could put a T-Tap on this, to a relay coil. The relay type you would need looks just like the normal relay, but has a N.C. ( normally closed ) contacts on it ( marked as 87A ).

Once you get the correct relay ( 5 pins, not 4 NAPA has them, AutoZone...got me ) here is a quick diagram on how to wire it up. Check the pin assignments against the one you purchase, just to be sure:



Any questions, just ask.

Good luck

 

Thanks SCully!!! That's perfect. Will do this weekend and let ya know how it works. Off to find a relay....

 

Don't forget the T-Taps. Scotch locks have a tendancy to stop working when left out in the weather.

The T-Tap, NAPA also has them. They are a 2 part item.
1st part, is kind of like a scotch lock, but it is a single stake through the wire, and it gives a female spade terminal.
The 2nd part is just a normal male spade terminal, that plugs into the 1st part.

I have had good luck with these out in the weather, and not giving up, where the scotch locks usually do.

The best route is if you are good with a soldering iron, is to saddle cut the camera wire insulation ( don't cut the wire ) and then strip off the insulation from the end of the wire to the relay. Wrap the relay wire around the saddle cut, and solder it into place. Tape it up good, and you will be all set, assuming you don't have a cold solder joint. This won't give up at all. The solder joint will hold forever, and there is no break in the camera wire to give you fits later on.

Good luck, let us know how it turns out, and take pictures and post them in your gallery if you can. The next member would love to benefit from your mod !

 

Yep, will take some pics. I can solder, but better yet, I ussually use marine crimps with heat shrink. I HATE those taps... I'll just cut the wires (there is already a joint there anyway, so I'll cut the old joint off...) and crimp on what I need with heat shrink marine crimps. They can be left under salt water for years and never rust.

Found a relay at Sh_t shack, SPDT, had 5 terminals on it. They are labeled:

Coil 1
Coil 2
NC
NO
COM

I assume the COM should be the input for the lamp power. The NC will be the output to the lamp. The NO will be left empty. The Coil will get the BU camera power in and out obviously. Sound right?

 

What I take these to mean :

Coil 1 : pin 85
Coil 2 : pin 86
NC : 87A
NO : 87
COM : 30

If you use this to the drawing, I would suspect it to work.

If you want to test it real quick, put the relay with the N.C. contact on the license plate lamp, without the coil on, and the lamp should still work.

You are good to go with the marine taps !!

Good luck.

 

never mind....

 

That's exactly what I was going to suggest: The NC relay that turns one of the lights out would be the way to go. That way, even if the light blinked out when you were backing up, you could just feign ignorance and worst-case, get a fix-it ticket. I suspect very few police officers are going to even bother to stop you when only ONE of the lights is blinking.

Also, inspection-wise, when you go for the inspection, just unplug the trigger wire from the relay so it won't turn the light off, then plug it back in when you're stickered. You could even do that right there at the inspection place.... whne they inform you that one of your lights goes out when you put it in reverse, you say, "Oh, really? Y'know, I was looking at that the other day and I think I have a loose connection up here somewhere.... let me see..." Then you pull the trigger wire off the relay and say, "There we go, that should take care of it!" Heck, you could probably even pull that with an officer too! Something like, "Oh, I was working under there the other day and I thought that connection looked loose." [Click] "There we go! All better!"

Just gotta have your story straight.

 

Project all done and function perfect.

I'm not worried about the light being seen going out. 1st, I have aux backup lights on my bumber, basically two 55watt foglights that come on when the truck is in reverse, they are so bright you can't see the license plate lights very good. The one light that now stays on, lights the plate just fine, it's hard to tell the other is even off.

How many times do you backup with a cop behind you anyway? (probably not a good idea, cause if you run into him, the light bulbs goings to be the least of the worries... ).

I'll post a few pics later. The only glitch I ran into was, I found my camera power is always on. So I couldn't use that as the "trigger" to the coil on the relay. So I instead used my backup lights power. They come on when in reverse, so that that worked out perfect. I soldered 4 wires abotu 8" long each onto the pins on the relay, then just covoered the relay in a big gob of silicone. I let it dry overnight and ended up with a nice waterproof wad of silicone with 4 wires sticking out. Then I just crimped those leads onto the following:

1) +12v Power from backup aux lights to one side of coil (#85 terminal on relay, see diagram above).
2) Grnd to other side of coil (I just ran a ground wire to the frame under bumber) (#86 terminal).
3) I cut the + wire (brown) going to the one lic. plate light, put one side on the #30 terminal.
4) The other side of the brown wire (which goes to the light) on the #87a terminal (normally closed).

So now, both lic plate lights are normally on, when the truck is put in reverse and power is applied to my aux backup lights, the left side lic. plate light goes off, and my video camera comes on with no glare.