Installing Aux Backup Lights....

chakis24 · June 13, 2010

ok, bought a cheap set of fog lights from autozone that im trying to hardwire so that they come on automatically with my reverse lights.

so heres what i did, connected the lights as shown in the diagram- mostly.

light one has a black ground and a white power wire. light 2 has the same. i connected the white wires from both lights to a splitter on a third wire. this third wire is spliced directly into the center pin (light green wire) behind my trailer harness (if i had used the switch, this wire would go to the switch along with another ground wire and the power wire from the battery). i know the lights are getting power because i have the under tailgate light bar which is also spliced into the light green wire- which still works. there shouldnt be a voltage drop (or at least not enough) since theyre in parallel.

i also tried splicing it at the tailight, but to no avail (i used the colored wire that went into the reverse light, i figured the black wires were grounds since they went into the red tailight as well). there is also a red wire with a built in fuse that i did not use- this could have also gone to the battery (but the diagram only shows this wire used when i have a two prong switch- this set has a three prong. the three prong requires a ground instead). it also doesnt help that the diagram shows a blue wire connecting the two lights together- there was no blue wire included, but a black one instead. i also had an extra red (which would have been the wire to the battery) and tried connecting the lights with that wire, but also did not work.

maybe if i splice each light directly into the light green wire? i also didnt hook up the ground on each light, could that not allow for the lights to come on? or is it the cheap connections they use? the connections are cylinders ends that you insert into an open cylinder that you pinch together and voila, connection (im actually thinking of avoiding these connections all together and splicing all the wires together).

this is the first time ive ever tried to wire something myself, and its not going very well.

any help would be greatly appreciated.

Blue2500CC · June 13, 2010

i also didnt hook up the ground on each light, could that not allow for the lights to come on?

From the sound of it, everything else is ok, BUT you NEED A GROUND for the lights to work!

I bought a set from Meijers that are packaged as "Back Up Lights"for my 2k CHEVY ( Oh snap, I am going to jail for saying CHEVY, CHEVY,.....). They worked great! I even mounted a set on my utlility trailer. And plan on a set for my new 2010.

Chris

chakis24 · June 13, 2010

i also didnt hook up the ground on each light, could that not allow for the lights to come on?

From the sound of it, everything else is ok, BUT you NEED A GROUND for the lights to work!

I bought a set from Meijers that are packaged as "Back Up Lights"for my 2k CHEVY ( Oh snap, I am going to jail for saying CHEVY, CHEVY,.....). They worked great! I even mounted a set on my utlility trailer. And plan on a set for my new 2010.

Chris

really? i didnt think a ground would negate the light from working. can i connect the ground to the negative wire in the trailer harness? i know i could also connect it to any metal on the truck, but i think the negative wire would be better.

khancock · June 13, 2010

Yes you need a ground. You could connect it to anywhere on the truck that is metal but your correct; your best ground would probably be the wire for the trailer since this is the harness you already spliced into.

chakis24 · June 13, 2010

Yes you need a ground. You could connect it to anywhere on the truck that is metal but your correct; your best ground would probably be the wire for the trailer since this is the harness you already spliced into.

well, i guess that makes sense- a ground would complete the circuit. alright, i'll try that tomorrow- hopefully i'll have some pics too. and just to be sure, that would be the negative wire on the harness, correct? since the power in my truck comes from the positive side of the battery. would the positive wire be continuously hot?

TexasAl · June 13, 2010

I might not be reading this right, but if you are not using a relay, I'd highly recommend you do that if you don't want to blow the fuses, or even a module with these back up lights. A relay is fairly cheap, and easy to wire up.

Al

khancock · June 13, 2010

I might not be reading this right, but if you are not using a relay, I'd highly recommend you do that if you don't want to blow the fuses, or even a module with these back up lights. A relay is fairly cheap, and easy to wire up.

Al

That is a real good idea if he is tapping off the reverse wire that runs to the tail lights. But if he wires it to the reverse circuit on the trailer harness unless he is towing a trailer with reverse lights he will never have any load on that circuit so it would be fine.

Blue2500CC · June 13, 2010

Think of it this way, if you go to vacuum out your truck, and one of the 2 prongs on the vacuum cord plug is completely broken off, then the electrical ciruit is not "complete", and the vacuum wont run. The BU Lights need to have a "complete circuit (circle)" to work.

As for the relay, I would agree if you tapped into the trucks tail light harness. But if you tapped into the trailer harness I think you will be ok, even if you have a trailer with BU Lights. I had a set on my 2K Silverado, and never had a problem when pulling my trailer that I had the same set of lights mounted on the tailer for BU Lights. The lights I used look just like THESE. I will get an exact model number when I get a chance. Cleaning the garage out I came across another set I had! They were only $20.00+tax. They have a shorter harness, no switch, and are packaged as "Back Up Lights" that mount to your trailer hitch with brackets.

Good luck!

Chris

i also didnt hook up the ground on each light, could that not allow for the lights to come on?

From the sound of it, everything else is ok, BUT you NEED A GROUND for the lights to work!

I bought a set from Meijers that are packaged as "Back Up Lights"for my 2k CHEVY ( Oh snap, I am going to jail for saying CHEVY, CHEVY,.....). They worked great! I even mounted a set on my utlility trailer. And plan on a set for my new 2010.

Chris

really? i didnt think a ground would negate the light from working. can i connect the ground to the negative wire in the trailer harness? i know i could also connect it to any metal on the truck, but i think the negative wire would be better.

chakis24 · June 13, 2010

thanks guys, but i cant figure out what the problem is. still no power. grounded them to the frame and nothing. unless the splice clips im using arent providing a good connection between wires i dont have a clue what it can be, im trying to find my tester to see maybe where im losing power but cant seem to find it.

the splicer the guy at autozone gave me say 16-14 gauge on them. thought that would be suffcient, but i took them apart on an extra wire (since theres slack now that im not running them from the battery) and they barely make it through the insulation. maybe thats it. what gauge are the wires in the harness? i also noticed that the ground wire (negative) in the trailer harness is much thicker than the rest.

[email protected] · June 13, 2010

If you spliced the lights into the light green wire and not the dark green on the trailer connector harness it should work unless your trailer backup fuse is blown. Put the truck in reverse and open the trailer connector and check for voltage at the middle pin(backup lights) it should have 12 volts or it should make your test light come on. If it doesn't your fuse is blown.

[email protected] · June 13, 2010

Does the diagram specifically say that black is for ground and white is for power? if not, that would be the first thing i would check

chakis24 · June 13, 2010

Does the diagram specifically say that black is for ground and white is for power? if not, that would be the first thing i would check

yeah, it says white for between the lights (well, blue actually but no blue wire was included), but doesnt say black for ground. but i figured this was the case since it specficially states red for power as well.

and a fuse, duh, forgot to check that. but i dont think it would be a fuse because my led light bar is spliced into the light green wire as well and still works. i couldnt find my tester so im gonna pick one up tomorrow on the way home from work. i put everything away for the day since i was getting frustrated and i'll pick it up again tomorrow from scratch.

anyone know what the gauge of wire into the harness is for the negative (ground-which is bigger than the rest) and the reverse? i may need new connectors if theyre too small.

[email protected] · June 13, 2010

well, if you have power, and you have ground...the lights should be working. so either the wires are switched...( black is hot, white is ground), or...the bulbs are burned out? or somethings not connected good enough

[email protected] · June 13, 2010

The light green is a 16 gauge, I would tap it with a blue squeeze splice(you could tap it with a pink if you had one). The ground on the connector should be a 12 gauge and will require a yellow squeeze splice.

chakis24 · June 13, 2010

The light green is a 16 gauge, I would tap it with a blue squeeze splice(you could tap it with a pink if you had one). The ground on the connector should be a 12 gauge and will require a yellow squeeze splice.

yeah, i have the blue ones. alright, i'll pick up the yellows when i get the tester. but the lights ground wire is smaller, can i use that with the yellow, or could the pink you mention be able to do both? thanks again.

and it seems lower gauge = bigger wire?