new LED light bar wiring issues

[dfl701]

ok i purchased a 21" led light bar from blitzpro. i got it all wired up kst night and tried it out and everything was great.

i followed this schematic to give you an idea of how everything is wired up.

so this morning i go outside to leave and smoke comes from the hood. my power cable from the battery and my ground are melting the sheathing off. i quickly disconnect everything and turn truck off. so heres my scenarios

1) i ran a main ground cable to the negative on the battery and then connected the ground from the switch, the light and the relay to my main ground cable by soldering them together. could this be an issue?

2) i have power to the light, but possibly connected something wrong?

3) my ign power from the switch is temporarily wired to my high beam fuse in my fuse box. this way the light comes on with my high beams.

what did i do wrong? i hate wiring and now i have to redo everything and i hope i didnt blow my light.

 

[dfl701]

Bump. I know there's some wiring guys here

 

[ryoken]

couple things..

first, wiring to the hi-beam fuse isn't going to make it come on with the hi-beams.. that's just a constant feed for the switch/lights..

second... you obviously have a dead short somewhere.. i would start by totally forgetting about the lightbar and fixing the bat cables so it's back up and running... than determine what you did wrong after..

just a word to the masses here... a very common issue I seem to see is people not understanding the purpose in a ground at a switch, THE only purpose and time a grd is used is if there is a light in the switch and you want it to light...

 

[dfl701]

Ok so basically bypass te relay and get it hot again. Then go back and add the relay. Should I ground at the battery or go to the frame?

As for the switch it does have a tiny blue led for power so I never looked at it that way. I will just ground the switch in the cab.

 

[ryoken]

Ok so basically bypass te relay and get it hot again. Then go back and add the relay..

i didn't say that... I'm guessing from what you've said, that you nuked the vehicles pos and grd off the battery.... fix the truck.. get it back to the way it was before you started adding stuff..

you need to be more clear as to whats going on here.. you say you have power to the led light bar still? than what exactly fried? and you said it was fine last night, so it worked?

connecting multiple grds is fine, but you obviously have a pos grounding out somewhere if you had smoke coming out... it doesn't matter where any of it is grded, the bat, the frame, dash sheet metal... that's not your issue, something hot is wired to the wrong spot...

 

[Fordum]

OK, Ryoken and I have two different ideas about what you said. I read it one way, he read it the other.
You said:

my power cable from the battery and my ground are melting the sheathing of

If, like Ryoken thinks, you are talking about the main battery cables, then forget about the light bar.
Whatever short you have is not in that wiring. I don't care if you ran 10 gauge to the light bars, it would melt and vaporize before the main battery cables got that hot.

If, like I think, you are talking about the leads to the lights, then you need to double check how the fuses are wired up.

If they are wired like you show, then you either ran waay too small a wire to the light bars, or the short is between the fuse and the battery.

Either the 3 amp or the 25 amp fuse should have prevented any smoke.

Since you say you came out and found smoke first thing this morning, I assume that you did not leave the bars on all night.
So, unless the switch shorted out and turned the relay on, there should not have been any power on the light bar wiring after the relay.

Do this:

Check the wiring between the 25 amp fuse and the battery for a chaffed wire or maybe having been run too close to an exhaust manifold.

Also, replace the "10 amp wire" with "25 amp" wire. Whatever size wire you are calling that.
Remember, the fuse has no way of knowing where the short is. So, if the short occurs in the heavier wire, the fuse will blow before the heavy wire gets too hot.
But, if you get a 23 amp short in the 10 amp wire, the fuse will happily supply the 23 amps all day as the smaller wire melts and catches fire.

Post back exactly which wires melted, and where in relation to the fuses they were, and we can go from there.

 

[dfl701]

Ok fordum you are correct and I wasn't very clear. That's my fault. The cables that melted are the 14 ga wires I ran from my battery to the relay. Not my batter cables themselves. I also have tested my light. It still powers on so it is not fried. So now the question is where was the issue. Unfortunately I can't trace wires because I promptly tore them all out as it scared the crap out of me.

 

[Fordum]

Ok, then that makes it simple.

First, 14 ga is too small for a 25 amp load. It might stand it over a short distance, but you are going to lose voltage due to resistance.

I would go 10 gauge from the battery, through the relay, to the lights. Don't forget the ground carries the same amount of current, so use the same size wire.

Put the fuse as close to the power source as possible. It only protects the wire after it, so if you have the fuse at the relay, then the wire from the relay to the battery is unprotected.

If you want the light bar to come on and off with the high beams like my old driving lights did, get the power for the switch from the high beam switch or one of the wires feeding the high beam filament on one of the headlights.

Then, whether or not they come on with the high beams is determined by the light bar switch.
And, if you are driving at night with them on and meet someone, dimming your headlights turns them off as well.

Put the 3 amp fuse for the light bar switch at the power source too.

If I had to guess, I suspect your power feed for the relay got pinched or had a hole rubbed in it between the fuse and the battery, or the wire was just not heavy enough.

A short in the power feed should not have melted the ground wire. Which makes me suspect that the wire was just not heavy enough to start with.

OK, just went back and reread your first post. Looks like you said that you purchased one light bar 21 inches long.
According to their website, it should only draw about 4.5 amps.

If you only have one, instead of the two on your schematic, figured you just cut a pasted that, then 14 ga is not too bad.

But, you need to reduce the size of your fuse to about 10 amps, and I would consider increasing the size wire to 12 ga just to cut down on voltage drop.