Fog light wiring/electrical question
 

Hi all,

Long story short, I installed led strips as drl's, and while they turned out very nice, I didn't really like the look, so I took them off.

In the mean time, I installed LED fog light units that I saw elsewhere in this forum. They work perfectly with the factory wiring, but I wanted to be able to turn them on independently of the headlight system. So, I hooked them up to the switch and wiring that I used for the old DRL's I took off, and just disconnected them from the factory harness. Everything works.

My question is: May I connect BOTH my secondary switch, and the factory plug/harness to the lights at the same time? Would I be risking any electrical damage if I turn on both the factory switch and the secondary switch?

My concern is that the secondary switch/power source will be sending current through the factory wiring harness and will damage the factory wiring/relay/fuses?

I'm by no means an electrical expert :o:p and while reading this post realize it might not make much sense, so see the attached rudimentary wiring diagram (the term diagram used loosely lol).

Contrary to the diagram, I do NOT currently have the factory connection hooked up. Just wondering if I can, so I have the option to use the factory switch in addition to the secondary switch that I currently have it hooked up to. I understand there will be some redundancy there.

Thanks all!

http://i60.tinypic.com/1ibeyr.jpg

P.S. - I just noticed my typos on the diagram above, please excuse haha...

you would have to install appropriately sized & oriented diodes for each of the power sources for your fog lights. I do not know how to size diodes, but there are electronics forums where I'm sure you could get help with that. I would not recommend it without getting someone good with DC electrical systems looking at your plan and specs.

Edit: You will not need to run a ground through the firewall. I'm sure your illuminated switch needs a ground for the little light inside, but other than that, you only need to send a 12v+ line through the firewall. Run that wire to a SPST relay coil lead, then to chassis ground out the other side of the coil. Then, through the relay, you can just run a wire off your battery or other always on 12v source to run your fogs. Always use a fusible link to prevent a fire caused by a short somewhere.

Thanks ccernst!

To clarify, I already have all the wiring installed that is in the diagram, with the exception of the factory connections are simply un plugged at the moment.

So, to me it looks like the easiest thing to do is simply put "blocking" diodes on each power source, and done?