BajaRunner

I saw some cheapo lights at the auto-parts store today. They were about 5"x2" lights that just had a pos and neg wire running out of them. They were selling for $5 a peice.

I thought it would be great to install these for backup lights and some aux lighting around the truck for camping.

What do I need to buy to get these things to work? Do I just need a switch? What is a point of a relay?

Thanks for any help!

BajaRunner

Also, I've seen a lot of rigs with square lighting that mount on the sides of the roof racks for aux lighting (for camping im guessing). Any idea on who makes these lights? Might be worth just buying something with more quality?

Bob_98SR5

SC,

take a look at my hella 500 writeup in the tech section (electrical subforum). that will tell you exactly what you need to buy and what to do.

if you have an aux fuse dist box, you are golden if not, you will have to hook it up directly to the battery.

914runner

I am planning on using some NAPA work lights. If those dont have the beam Im looking for, I was going to go with the slightly more expensive Hella work lights.

Go look through a Hella catalog, They have tons of cool stuff you probably havent seen before! Some very nice sealed fuse and relay blocks.

BajaRunner

Hey Bob,

I read your writeup.

Say I have 2 backup lights and 2 side ambient lights. I want to run them off of seperate switches. I will need two relays ? I dont understand what the relay does. I was under the impression that the switch just switched over power to the lights so they were not on all the time.

Bob_98SR5

if my knowledge of relays is correct...

Yes, you will need two relays. The relay is placed in between your lights and your power source. Assuming you had the lights wired up to the battery, your lights would be on all the time. Stick in a relay in between that is controlled by a switching device, you will be able to control the on/off of the lights.

you can wire up those relays in many different ways. again, just follow the writeup and the process and you'll be able to control your backup and side lights independently from each other.

bob

kpooch75

Not quite sure about all that, so I'll add my $0.02. You don't need a relay to run backup/aux lights, or at least I didn't use one. I ran power from the battery to a regular switch and then to the lights and it works fine. Now, if you wanted to wire the lights so that when you flip the switch then that would enable the lights to come on only when in reverse, then you would need a relay. As I understand it, the relay is like a second switch that only operates under certain conditions. For instance, if you tap the wire that turns on your stock backup lights to one terminal of the relay, then the relay will receive power when you are in reverse. Thus if the switch is flipped while in reverse the aux backup lights will come on. It's the same thing that people do when wiring driving lights that only come on when the high beams are on.

Any of that make sense?

BajaRunner

Yeah, that makes sense for sure.

So the lights will function fine if I just run power to the switch, and then the lights.

I just want to use a switch to turn on backup lights. My truck is so tall that the stock backup lights dont do anything for me. In some dark areas, some aux lighting would be nice with a switch, and not all the time. I thought the wiring would be easy, but, I just got confused with all thte other stuff.

Say I have two backup lights. They both have power and negative wires. Do I just splice the positive wires together and run a single wire into the switch?

boogyman

ok, i think you guys need a little help with how a relay works... i drew up a quick picture to help explain... it's attached below.

Think of a relay as a powered magnetic switch. All a relay does internally is activate an electromagnet to close another (high current) switch. The reason you need a relay is because typcially you don't want to put a switch directly into high current circuits (like a 100watt off road light, for instance). If you DO put a switch into a hight current circuit like that, you risk wire overheating, electrical fire, etc, etc.. With a relay, it does the high current switching for you, and all your little switch has to do is activate the low current electromagnet inside the relay. If you look at the diagram below, that is how you should wire up your offroad lights. The right half of the diagram is a cutaway view of the inside of the relay (the squiggly mess is the electromagnet). When the electromagnet is activated, it pulls down the switch on wire 3 to make contact with wire 1, and voila, you have power to your lights.

BajaRunner

Sweet man, that makes great sense.

I did some reading this afternoon on the whole thing and Im understanding why the relay is needed now.

Thanks !

waskillywabbit

iTrader: (-1)

There is a STICKY that has all this information in the General Electrical tech part of the forum.

garrett1478

boogyman said it. use relays to handle the current, you dont want a lot of current going through the switches on your dash

http://electronics.howstuffworks.com/relay.htm

www.howstuffworks.com is a great site

BajaRunner

No there aint!

I read all the electrical stuff before i posted. I am such a noob with electrical stuff, I have no idea what even the tech articles are talking about sometimes. I didn't understand what the relay did. None explained it how the guy above explained how it works, and what it does, and what its for.

I see how you wouldnt want 100 watts of power running through the switch though, it makes sense.

So the relay must be wired directly to the battery terminal eh? You couldnt splice the relay itself into the fuse box right? It draws too much power?

waskillywabbit

iTrader: (-1)

YES THERE IS!

https://www.yotatech.com/forums/f131/

Look at the top of the page.

GSGALLANT

Not necessarily... it depends on what you're running. If you have two 55W lights (110W total), your current draw will be around 9 amps, which you can easily run through an aux fuse panel. You must do the calculations and figure out what works best for you in each situation.

If you have an aux fuse box rated for a total of 30 amps and it has 6 fuse slots, you probably wouldn't want to run say... three 100W lamps off of one 30 amp fuse and have 5 fuse slots that you can't use. However, if you run the power for those lights directly from the battery (through an in-line 30amp fuse), you can use power from one of the fuse slots on your aux fuse box to control the relay through your switch in the dash (the control power for a relay is low - therefore its current draw is low.)

BajaRunner

Oh.. You mean THAT forum. Damnit I didnt even know that forum existed.

I hate it when your right. And when your right, your right. And you, you're always right! (Spaceballs)

Okay, thanks GS for that extra bit of information!

waskillywabbit

iTrader: (-1)

"Wabbit knows. Wabbit is WISE." (Twister)

boogyman

boogyman

Glad I could help.

FingerMan20

sorry to hijack, but where would the aux fuse box be located, and if you didnt have one, what would you do?