Anyone wiring/wired switches in their car? I'm trying to hook up a master switch, a switch for my radar detector, switch for my overhead light I installed, switch for the passenger light, switch for the floor lights and a switch for the back lights. I've been trying to figure out ways to hook it all up... I wired up the master to the 12 volt and ground through the cigarette lighter and the master worked, but then when I wired up the next switch the fuse blew. Anyone done this? I'm not that good with switches.

 

It helps me to write down primitive schematics on paper first, then wire it up after I know where I want each wire to go. The important thing is to make sure it is fused and that the fuse is as close to the power source(battery) as you can.

For example, a friend of mine wired Bat---switch---fuse---light----ground. Worked, then he accidentally knocked some wires off the switch, he hooked it back up, but did it wrong. There was a direct ground that powered the light in the lighted switch, he hooked that too the acc point and when he turned on the switch it directly grounded the power wire, no fuse, lotsa stinky smoke.

It will probably take some practice, but you just probably had something miswired. Also, keep track of how much current each device is drawing, if you have too many devices on one fuse, it can overload.

HTH »keith

 

Is it bad to hook the power straight to the supply of the master and take the ground wire, extend it out and sort of vampire tap each ground terminal on the rest of the switches into the ground wire? That's what I tried doing, and that's how the fuse blew. Although, I hadn't hooked up all the switches which was the weird thing.

So I didn't really know how to hook up the rest of the switches to the master switch, so that the alt switches don't turn on unless the master switch is on. That's probably my biggest problem. I've been writing everything down it helps a lot. Man, this is so confusing haha.

 

Why is there a ground wire on your switches
Are they lighted switches ?? I'm a little confused when i try to picture what you got going on there.

 

i know very little about wiring, but it seems a relay may need to be a part of this circuit. basically there is a limit to the amount of power you can simply switch without excess heat and smoking wires. you might post in the electronics section, they'll know better.... good luck

 

Maybe a visual will help:

The amp ratings I posted are just for example only, you'd have to look up what you have.
As you can see in this example, if both the interior lights and fog lights are on at the same time, thats 20 amps and would blow the fuse. You need to consider total load when designing a circuit.

Other considerations:
the wire should be rated higher than the fuse, if you do an I-net search, you'll find charts that list recommended amps for a particular sized wire.
The switch should be rated higher than the fuse.
You could even individually fuse each branch circuit allowing a smaller wire for that circuit and better protection.
Relays, as mentioned, open up new possibilities for your setup. If you are using micro switches, you will probably need relays because they can only handle a small amount of current.

Since people often have trouble understanding relays(I know I did), I'll do a simple schem just like this one, but with relays. It will look much more complicated, but if taken one part at a time, its simple. A relay is nothing more than a switch controlled by another switch.
Why would you control one swith with another switch when you can just use the first swicth?
The main reason is current carrying capacity, the switch you want to use may be too small for what you want to run. Other reasons might be to convert a NO(normally open) switch to a NC(normally closed) circuit. If that sounds confusing, don't worry about it yet. It'll be more understandable when you start doing it.
»keith

 

This is the version using relays. As you can see, the number of wires quadripples, now you know where all the wires in a wiring harness come from.

I used small, low amperage switches.
A main fuse & branch fuses for each circuit.
I lumped 3 relays on one circuit in anticipation that low amperage devices would be on it. This saves unnecessary wiring and fuses.
The smaller fuses allow smaller wire, for example the 3 amp switch circuit can use very small wire, whereas the 15 amp fog light curcuit needs heavy duty wire. (you'll have to look that up).
The relays are standard "bosch" 5 pin relays, they come in fog light kits and are available at electronics places/catalogs. Mail order places like MCM electronics even have harnesses that plug right into relays so you don't have to wire individual spade connectors at the relays. This way, if you have to replace a relay, you won't accidentally mix up the wires.

I only used the NO(normally open) contacts, but I drew the NC(normally closed) contacts so you could see them. Some cheaper relays, light those in fog light kits, do not have the NC contact. Its rarely used, but it would be for something like a very simple alarm, or a "dummy alarm" that is only blinking leds. If you wanted it on with the car off, you do not want the relay "activated" or "engergized" as it will kill your battery, so you use the NC contact, you turn the key on, it turns on the relay, which would turn "off" the alarm. clear as mud?

Microsoft Paint works well for drawing up circuits.
»keith