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Discussion Starter · #1 ·
So I couldn't find a good diagram on how to do this so figure I would post. I have 2 separate harnesses with a relay, 40amp fuse, and a switch on each. I wanted to combine these so they both ran off 1 switch instead of 2 different switches. Could someone explain how I go about doing this?
 

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The "easy" way would be to find both wires that are going from your switches to your relays (that are making the relays switch state (open/closed)). DO NOT USE THE WIRES THAT ARE GOING FROM THE RELAY TO THE EQUIPMENT, YOU COULD OVERLOAD THE RELAYS OR THE FUSE.

Cut both wire, take both ends that are connected to a relay and connect them together. Add to this connection, one of the wire end that is connected to a switch.

How to do the connection depends on how clean and nice looking you want this to look. (Electrical tape, male female connectors, etc...)

After that, you can remove the excess switch and whatever wiring comes from it (it might or might not have a ground wire connected to it depending on the switch type).
 

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Discussion Starter · #3 ·
So from what I understand, just cut 1 switch off and use that wire to tap into the other switch wire? This is what I assumed, just didn't want to mess up a good harness doing it wrong.

I don't care how bad it looks as long as it works. It'll be tucked away.
 

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Yeah that's about it.

A relay needs a very low power input to works. So you can easily use the same switch output to power both relays. If you have more questions, simply contact me by PM and I could help you draw the diagram to understand how everything works out in the end.
 

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You can tie 2 switches together in a circuit any way you like, following voltage rules, as long as the total load does not exceed circuit limits (ie-protection).
Fuses protect circuits (ie-wiring). A 40amp fuse will protect about 10ft of 8ga wire (with minimum voltage loss).
You can undersize a fuse (20amp fuse protecting 8ga wire) but should never undersize wire gauge (20amp fuse protecting 18ga wire).
In other words, it really doesn't matter if you hooked up 10 components drawing 1amp to a 20amp protected circuit as long as the total component load (in this case 10amps) does not exceed fused protection, and that each 'circuit' (wiring gauge/length used) was also rated for use at or below 20amps.
 

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Discussion Starter · #7 ·
You can tie 2 switches together in a circuit any way you like, following voltage rules, as long as the total load does not exceed circuit limits (ie-protection). Fuses protect circuits (ie-wiring). A 40amp fuse will protect about 10ft of 8ga wire (with minimum voltage loss). You can undersize a fuse (20amp fuse protecting 8ga wire) but should never undersize wire gauge (20amp fuse protecting 18ga wire). In other words, it really doesn't matter if you hooked up 10 components drawing 1amp to a 20amp protected circuit as long as the total component load (in this case 10amps) does not exceed fused protection, and that each 'circuit' (wiring gauge/length used) was also rated for use at or below 20amps.
I pretty much understand that for the most part. Just was confused on how to combine the two harnesses.
 
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