wiring offroad lights

[Tennessee Jed]

Stupid question, but can someone point me to a source of information that will explain to me how to wire offroad lights? I want to put 2 100w lights on my front bumper.

I have a mental block where electricity and wiring are concerned. I've looked at wiring diagrams until my eyes cross and all the explanations seem to leave out basic information, or assume that you have basic understanding of wiring, which I don't.

I believe I need to get a spool of probably 10 ga. wire, a 20 amp relay, and a fuse (I think a fuse goes near the battery where the power wire leaves, to go to the lights), but I'm really unable to take it much further than that.

If there's no good source of info I'll just pay to have the job done but I want to understand this crap and this is a good first step. What I want is just simple, clear, step by step explanation. I don't know what it is with me and electricity.

I've searched and found nothing here - apparently not choosing the right search words or something.

Many thanks.

 

[sandcruiser]

first, a good link to how a relay works: The Bosch Relay Unraveled

what you want to do is pretty simple:

materials:
10ga wire (good for at least 20amps, which is more than you need)
fuse holder
20 amp fuse
18ga wire
switch
terminals to connect 18ga wire to switch and to ground, terminals to connect 10ga to relay and to lights and to ground
bosch-style relay (with terminals 30, 87, 86, 85 printed on it) at least 20Amp capacity

connect the fuse holder to + on the battery, then to the 87 terminal on the relay.
Make a jumper that goes from the 87 to the 85 terminal with 18ga wire.
run 18ga from the 86 terminal to your switch in the cab.
then run 18ga from the switch to a convenient ground in the cab (any screw/bolt in steel should work)
*this way when you turn the switch on, it completes a circuit from the relay to ground, which activates the relay and allows power to go to your lights*
run 10ga from the 30 (NOT THE 87a) terminal of the relay to your first light's + terminal
run 10ga from that same terminal to the + terminal on the 2nd light
use 10ga to connect the two negative/ground terminals on the lights to ground. make sure it is a good connection to ground- frame is better than bumper

That should do it.

If you want to get fancier, you can get fancier. But this is the simplest way to wire lights and should work well for you.

The theory behind it is that you are running hot to the 87 and 85 terminals, then grounding the relay through the switch to energize the coil. When the coil closes the contacts in the relay, power flows to the lights, then to ground.

Good luck. Work slowly, make sure your connections are done well. A decent wire crimping tool is a good thing to have. Heat shrink tubing on the connectors will help keep dirt and water out, which will help things last longer.

 

[Tennessee Jed]

Awesome, thanks very much. I have seen diagrams that show a switch with three prongs coming out of the back. Is this the kind of switch I need to get?

 

[sandcruiser]

you can use almost any switch, the minimum that you need is a SPST (single pole single throw) switch
if you want to use an illuminated switch, you'll have to make some changes to the way your wires are connected

there are a variety of ways to hook up the switch, but they require slightly different wiring to the relay.

 

[SPDSHFT]

also, if you go into almost any auto parts store, they should have the whole kit ready to go with everything. There is a company out there call "Rally" that makes a good kit and they sell it at most Pep Boys, NAPA, Auto Zone, Kragen, Walmart, etc. Ive used them several time on my own vehicles and others Ive wired up.

#3187 RALLY AUXILIARY LIGHT WIRING KIT (s) : eBay Motors (item 190322976405 end time Mar-17-10 16:56:56 PDT)

 

[Tennessee Jed]

Thanks guys!