I have a 2008 F250 Super Duty with the Lariat package.
What I would like to do is have the fog lights controled by one of the aux panel switchs.
I have the panel wiring layout for one of your other threads. What I need to know is what wires I need to diconnect and which switch (amp) should I use.
If I was going to do this I would go buy new bulb plugs that fit the fog lights and wire them to a new 8 gauge or heavier wire from the positive side of the battery with a fuse right at battery to a relay then run the wire from the lowest amp upfitter switch you have open to the relay and ground the relay as close as possible to the relay. This way you are getting the most power possible right to the lights you could even switch to a brighter bulb.
8 gauge or heavier wire from the positive side of the battery
You won't need 8 awg wire. 14 or 12 awg is sufficient. I believe the fogs are aprox. 45 watts each. but if i assume 55 watts @ 12V or 13.8 = ~9 Amps.
If you decided to use a higher wattage bulb you may want to consider the 12 awg but keep into account the housing/lens may not handle the excessive heat.
Waigon's idea is good to keep them isolated from your existing system so they won't cause any issues and you can easily return to the stock system.
I'm using (mine are OEM aftermarket with independent wiring to a relay/switch)14 awg stranded THHN which has a 600v insulation and 90deg.C temp. rating and is gas/oil resistant. The 14 awg will safetly handle about 15 amps. The relays you can get at any automotive store.
If the wiring is the same as the 05-07. there is a factory break/splice on the frame in front drivers wheel well. You could tap in there.
I have factory fogs to my aux switch. The Aux switches already have relays. Owners manual tells you the relay amps per switch.
On my 2003 I had done a mod that allowed the fog lights to stay on with the high beams. Does this work on the 2008's?
NO! which really bummed me out. Someone on here using a wiring schematic figured out how to do it but it is much more involved then cutting one wire and grounding it. Your best bet is to buy a Bright Box. I may try the suggested way on here after truck is out of warranty but I might just do like the OP said and hook fogs up to a switch.