got these switches for some of my lights just wondering how to wire them because Ive never used these switches before, as much detail as you could give would be appreciated!
These are the switches I am dealing with the top little post with screw says on and the bottom says off. Thanks!
-Joe

 

That's as simple of a switch as you can get. Power goes in one side, comes out the other.

Here's a simple schematic I've used in the past. Follow this, paying attention to the proper fuse rating for your lights and you'll be fine.

 

do I need to ground the switch if there is no indicator light?

 

If there is no indicator light, there will be no grounding post. The switches you have only have two posts. In, and out. If you don't want an indicator light as shown in the schematic, simply forget it exists.

What's happening in the circuit here is probably the simplest thing you'll ever wire up on a car.

The relay in the center is the heart of the circuit. You can get these online, from junk yards, auto parts stores, etc. Most are rated for 30/40 amps, which should be plenty for your lights.

In the diagram, only four of the five pins are being used. 87A can be ignored entirely. 86 and 85 are the 'trigger' pins. When current flows through these pins, a connection between pin 30 and pin 87 is established, allowing what it is controlling to do it's job. Generally speaking, the relay doesn't care if 86 or 85 is connected to ground, so long as one of them are and the other receives 12 volts. In this case, they've chosen 86 to be ground and 85 to receive 12 volts.

On pin 85, we can see that it leads to one side of the switch, out the other side, and to the fuse box. This is where pin 85 gets 12 volts. In the fuse box, you will find several different arrangements. Some fuses are on the ground side, which cannot be used in this configuration (at least not without some changes to the circuit). Some fuses will be hot at all times, and others will be hot in run only. Depending on what these lights are supposed to do, I'd recommend choosing a fuse that is hot all the time. To properly tap into the box, you will need an 'add a circuit'.
These can be found online, at hardware stores sometimes, auto stores, etc. Make sure that it is for the 'mini fuse' size boxes, otherwise it won't fit. You will also need a small fuse for this. Find the lowest possible one you can. This side of the circuit doesn't draw much of anything. Note that there are two fuse slots in this device. One is for the circuit that was there already, and the other one protects the wire coming out. Use a meter to determine which is which, if the instructions don't say.

Anyway.... Once the switch is turned 'ON', the relay will make a 'click' sound. This is the coil inside making contact between pin 30 and 87, allowing current to flow from the battery, through the relay, and to your lights. Simple, just be sure to ground your lights. Some may only have one wire, in which case it grounds through it's mounting hardware. If this is the case and you're mounting them in plastic, you'll need to run ground wires to the lights for them to work.

Something you need to be mindful of is the wire gauges you're working with. If you don't use a wire that is thick enough, it will melt and send your truck up in flames. Use this chart to help you determine what gauge wire you need. Routing string where you want the wires to go, then measuring the length of the string will make things easier. Note that wire size, in this instance, matters only on the connections from the battery, to pin 30, out of pin 87, to your lights, and then ground.



Let's say each light draws 10 amps. Since both lights will be on the same wire, 20 amps of current will flow. If you run the wire over a total distance of 15 feet, following the 3% voltage drop range (good idea for best performance of lights), you'll need wire that is 10 AWG or bigger. It's a good idea to go to the next size up so the wire can handle more current if something goes wrong.

As far as fuses go, this also takes a little consideration. AGain let's say both lights, together, draw 20 amps. Logic would say you want a 20 amp fuse, but that's not entirely correct. When something first turns on, it will draw more current for a split second. This can be enough to blow the fuse, leading you to believe something's wrong, when in reality it's not. Rule of thumb is to use the next size up fuse. 20 amp current draw, 25 amp fuse. 5 amp current draw, 10 amp fuse, so on and so forth.

One last thing. How you make your connections is very important. Inside the cab, you can get away with using crimp style connectors or solder. Inside the cab isn't exposed to the elements, so there's little to disturb them. Just don't use wire nuts, that isn't acceptable for an automotive application. They fall off and wind up shorting things out.

In the engine bay and outside the cab, however, things are a different story. Rain water finds its way into everything, including salt and other corrosives. This is where only one thing will last over time. Solder and heat shrink, end of story. Other styles of connectors will corrode over time and stop working.

My father, a long time ago, used to work for a towing company. Their cab lights used crimp and t tap style connectors. Well, guess what happened. More often than not, he would find himself fixing these connections, until he went to his manager and got permission to solder the wires. The problems stopped recurring after that. One could say that "It's old technology, it's way better today" but at the end of the day, all a crimp or T tap does is squish metal together and over it, rather poorly, with plastic. It's not strong, it's not weather proof. In contrast, solder melts and fuses wires together; like welding does with two pieces of steel. You'll thank yourself later if you solder them today. If you don't have an iron, pen style soldering irons can be had for cheap. Heck, I use a harbor freight model and 60/40 rosin core solder (can be found at hardware stores) along with harbor freight heat shrink to great success. You can use a lighter or heat gun to shrink the tubing, just be careful not to scorch it.

To connect to the relay, however, there's one thing I also recommend. Either a socket for it, or you can buy a pack of spade connectors and use them in another way. Pull the plastic off with pliers, crimp the wire down inside then solder the wire and connector together, using heatshrink after to cover the connection. Lasts long, looks nice.

 

ok............. I'll try my best, thats a lot of electrical work