fog wiring

In the past when I've installed fog lights in my past trucks I've always wired them one of two ways (of course using a relay): to a parking light wire or to a low-beam wire. I prefer to wire them to my parking lights because I like to run with just the parking lights and the fog lights on during the day and by wiring them to the low-beams you can't do that. But really the legal way to wire them is to the low-beams because they will shut off when the high-beams are flipped on. So here's my question: is there any way possible to wire them so that they will come on with just the parking lights or the low-beams but still shut off when the high-beams are flipped on?

The other reason I'm interested in this is because I am planning on installing a remote start system in my truck soon, and the particular system I'm looking at flashes the parking lights when the truck is remote started. So if the fog lights are wired into the parking lights they will flash too, making it easier to see from a distance if the truck actually started or not.

Here's a diagram building on Hymer's suggestion.  The relay on the right activates the relay for the fog lights, then when the headlights are turned on, the relay on the right kills the connection to the fog lights.  The relay on the left is necessary to carry the high current load to the fog lights.

Your picture isn't working, only showing a red X.

Sorry, heres the diagram

So correct me if I'm wrong, but after reading through this post and some info I'm under the impression that a 5-pin relay can also act as an A/B switch. Pin 30 would be your source, and pins 87 and 87a would be your alternately switched devices if you didn't want them to be hot at the same time (only one can connect with pin 30 at a time). If this is true, this leads me to another idea

Hoss10,  your thinking is correct! 

Welcome to the world of relay "logic"!!!   Relays are inherently simple devices, however, multiple relays can be wired together to perform a wide variety of tasks.  Most tasks can be handled with two or three relays, however, you may see 8 or ten relays comprising a complex circuit.  The limit seems almost endless!!

Stick around this site (check out the relay forum) and you'll see some pretty smart people post some really slick relay wiring diagrams!  You'll end up learning a lot about relays, I know I have.

Another related question: would 16 gauge wire be sufficient to wire all of this or would I be better off going to 14? Also, does anyone have any recommendations of any sites to buy some rolls of wire from? I checked out www.allelectronics.com and they didn't seem to offer any rolls of any type that I need.

16 gauge wire is fine for terminals 85 and 86, they only activate the relay, so since it takes very little current to activate the relay, about 200ma, you can use a smaller gauge wire.  Your feed and output wire size is dependent on the current that the output device will use and the length of the wire from the relay to the output device. 

So you would have to have an idea of how many amps the fog lights will be pulling and how long of a wire you need to where the lights are mounted.  14 gauge might be marginal for fog lights, I would use 12 gauge for both the power feed to terminal 30 and the output feed to the fog lights.  Same goes for the ground for the lights. If you use 12 guage for the 12V feed, then you need to use 12 gauge on the ground coming from each light.

Your local auto parts store should carry primary wire in several gauges and colors in small 12-25-foot rolls. I would try there first.  Wire is like everything else, you get what you pay for. Here is a site I found that has an assortment of inexpensive wire to choose from:

https://doityourself.com/store/wire.htm