Reverse lights

Hello,
I just installed some 18w led lights on my trailer hitch for more light in reverse,
I try to wire them to my stock reverse light wiring but I get nothing, there power at the stock wire and I have power in the wire going to lights.. but no lights.. I sat a battery on the tailgate and hooked the wires to it.. boom! Lights come on.. what am I missing?? To may amps draw for stock wiring?? Someone please help... thanks

 

Likely not enough juice from the stock harness.

Might want to use a relay, and wire the lights directly to the battery. Wire the relay to the reverse light circuit.

 

Some LEDs need to be installed one way. If the polarity is reversed they won't light. Did you try flipping them 180 degrees? LEDs should draw a lot less current than incandescent lights, so if the incandescents light reasonably well, then you should be getting enough current.

 

For a comparablely sized LED, yeah, leds use less current, but an 18w led is a lot bigger than the incandescent reverse light bulb he’s trying to power it off of.

I would think it should be enough to at least get some light out of the led, so def weird op isn’t getting any light from it, so may be a polarity issue.

@vtlogger, I just replaced my stock reverse bulbs with some superbrightLEDs and they are amazingly bright. Just plug n play. Just food for thought...

 

Yeah, should have looked in to brighter bulbs.. I'm not sure about the whole polarity thing ( under standing it ) I do know if I hook them to the battery they come on but won't when hooked to the stock wires .. I did the same thing on my old Dakota and never had a problem.
That's why I'm not sure what I'm doing wrong

 

I think he is mainly referring to some bulbs are polatiry specific. Most of the incandescent bulbs you push in (vs. screw in) you can put it both ways, and usually it doesnt matter, but with he LEDs it does. Push in, and if it doesn’t light up, you just turn it around.

But that’s JUST the bulb.

If you have a pod or otherwise have a red and black wire to hook to, you shouldn't need to worry abot polarity.

If your lights have a manual, it might say if it has a min voltage, or a min amperage it needs to run.

It is a little weird that the lights don’t come on at all. the other possibility is maybe you hooked up the wires wrong, or misidentified the back up circuit... I've done dumber things, lol

 

Got a link to the lights we can look at?

 

Yeah, it may be impossible to install them reversed. I was thinking more of the type of bulbs that illuminate the gauge cluster and warning lights or the dome light. Those are symmetrical and you can turn them 180 degrees so the positive and negative terminals get reversed.

I would think the circuit could supply enough current to short the fuse. I mean if the LEDs were trying to draw THAT much current at 12v the fuse would blow. Even a very bright LED should draw less than a regular incandescent. There should be a huge voltage drop just from the wires going back to the trailer.

Maybe the contacts on the LED bulbs aren't sticking out far enough or something about the geometry isn't allowing them to make contact with the terminals. If the LEDs work directly at the battery and the socket terminals have 12v then the LEDs should work. Sounds like one of those things that if you sleep on it, you wake up and realize what the problem is.

 

Bad ground?

 

Sorry guys.. I may have not been all that clear
.the lights I'm referring to are 18w pods that I installed on my receiver hitch, there's 2 of them , I wired them together and ran the wires to my taillight where I try to tap in to the reverse light wire..
I checked the ground and it's fine and have power..
I wired up another pod I had tonight and it works, which makes my think there's not enough power to run 2 pods together
And I can make them work if I hook them directly to the battery. . I'm at a loss with this one

 

LEDs need a certain amount of voltage or they don't work at all. They aren't like light bulbs that just get dim.

Are you putting a them in parallel? 36w of LEDs is only 3 amps, so I would be really surprised if the voltage drop is that bad.

 

I had no problems running both types of extra reverse lights .spliced to one reverse wire no relays.

If your load was to much it would open the fuse

If the lights work when hooked direct to a power source .

Your stock reverse lights are on but the LED lights are not working must be a wiring problem.

Just where are you grounding the LED lights ?

 

I used the ground in the stock wiring and also grounded to frame with no luck... like I said if I run the wires directly to my battery they work. They just won't work if I hook them up to stock wiring so they ll come on when I put my truck in reverse

 

Could you post some pictures? Including the wiring plugs, light specifications from the manufacturer, and location of where they are going?

 

Time to break out the voltmeter and check for voltage on the wire you think is the pos(+) wire for the backup circuit, and use the frame as ground.

It sounds obvious, maybe, but verify that the wire you're using is actually the (+) for the backup lights. zero volts when in park/neutral, some non-zero value, probably ~12v when in reverse.

Or, depending on where you spliced off of, try your turn signals to see if you accidentally spliced off one of the turn signal wires...

 

The frame can be a rather poor ground

because I work on trailer lights often

I run a extra ground from the battery to the frame .

The ground going to the engine block only gets to the frame via the engine and Transmission mounts

Just how did you make the splice mechanical connection and solder ??

You are testing this in reverse with the ignition switch on and the stock back up lights are on??

Cause a fuse to open??

Just what year truck are you working on?? On my 2000 the wires for the back up lights Red / black stripe The Ground is White/Black stripe

 

Wyomingo9
My truck is a 2004 .. yes red wire black stripe + white wire black stripe - .. yes key on truck in reverse . The red/black wire is the only wire I'm getting power out of

J $
I'll try to post pics tomorrow afternoon with info on box

I'll also try to ground from battery to black wire on light to see if that help... thanks to all for the help

 

Any Luck with this?

 

Sorry none yet, got shot in the ankle with a nail gun so haven't really messed with it, hopefully I'll be back at it this weekend, it's really driving me nuts I can't figure it out.. but I'll get pics posted up soon

 

Use the same ground (white/black strip) that is being supplied to the light rather then grounding to the frame