wiring a 3 pin switch that actually has 4 pins


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Old 05-07-14, 07:12 PM
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wiring a 3 pin switch that actually has 4 pins

hi,

I ordered a 3 pin light switch to install on a light in my car. Now that I've received the switch I see that it has 2 regular sized spade connectors and then another 2 small connectors. How do I go about wiring this switch? Do I have go out and find smaller connectors for my wires now?Name:  2049_2.jpg
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I'm a total amateur and I've already caused a messed trying to wire up a 6 pin switch. I bought this switch and now am not sure what to do. Any help would be much appreciated.
 
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Old 05-07-14, 07:38 PM
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Normally there is a wiring diagram on the switch. Look on the other side.
 
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Old 05-07-14, 07:58 PM
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I can see a + and a - on the switch near the smaller terminals, that leads me to believe the switch has an LED internal for an indicator or locator light. If you have no need of the internal light then ignore the smaller terminals and just use the two larger terminals in series with one lead of the power supply and the load.

If you DO want the indicator then you have to observe the polarity when connecting. And yes, you DO need smaller terminals for the connection.
 
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Old 05-07-14, 08:34 PM
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that was quick ...thanks guys

There was no diagram on the switch.


Yes there is an LED on the the swith.
Can I just splice my hot and ground wire that I am going to use or do I have to run two separate wires for the led?
 
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Old 05-07-14, 08:50 PM
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What's throwing you off is that lighted switches for car applications normally have three pins. Two for the switch and one for the internal light ground. The internal light gets its power feed from either the input or the output that you are switching (depending on if you want the switch lit at all times or just when it's flipped on).

This one has a 'fully independent' light. This setup is normally reserved for certain types of installs, but it's not a big deal. If you are switching a positive circuit, just add a little jumper to connect the switched side (the outer large terminal marked 1) to the small + terminal. The small - terminal gets connected to ground.

And FYI the large terminals are .250", and the small ones are .110". Any decent auto parts store or car audio shop should have both sizes.
 
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Old 05-07-14, 09:15 PM
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thanks jerseymatt...your explanation cleared it right up for me. I think I can do this now. thanks for the info on what the actual connectors are. Now I don't have to be so vague when I ask for them at the store!
 
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Old 05-08-14, 08:01 AM
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You can also solder directly to the pins.
 
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Old 05-08-14, 11:12 AM
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You NEVER solder to the pins in an automotive switch. You solder the spade/ring/fork terminals to the wire, you solder splices (especially under the hood because crimps are weak and will rot) but you don't solder wires to devices. That's bad juju.
 
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Old 05-08-14, 08:40 PM
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You NEVER solder to the pins in an automotive switch. You solder the spade/ring/fork terminals to the wire, you solder splices (especially under the hood because crimps are weak and will rot) but you don't solder wires to devices. That's bad juju.
Interesting. I always thought it was acceptable to solder directly to the terminals because many listed products I've taken apart have soldered directly to the pins, including expensive UPS's and surge protectors. Then again, I don't touch automotive wiring unless it's 120V and up.:whistle:
 
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Old 05-08-14, 09:01 PM
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You can solder onto a switch but it must be fast and controlled. Most people would use too much heat rendering the switch useless.
 
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Old 05-09-14, 07:20 AM
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That wasn't really where I was going with it.. But since you mentioned it, it's not people "using" too much heat per-se, it's usually using a weak iron that causes issues. For soldering terminals you need a high-power gun that can heat the tab up really fast. With a low power iron, the heat wicks away into the mechanicals and wire as fast as it's being applied, so by the time the tab and wire get hot enough to melt the solder, the plastic is all soft and the springs pop - and the insulation on the wire is melted 2" back.

The reasoning for not soldering to devices in automotive is that usually switches like that are mounted to a dash/trim panel that will eventually have to be removed again to get at something else - or the switch may get hit by something and broken and need to be replaced. If you don't have a quick disconnect method, you're going to have to cut the wires and solder it again.
 
 

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