So is there an easy way to have them just always on? I like how they look with the DRL's on in the day.
Use the link to the rubber band trick that RedRocket posted. Otherwise you need to do some wiring work.
And- for the method listed above... where they turn on with the switch... would it be possible to give a how to for dummies on the wiring of this? I don't mean to be a pain... I am just not a professional at this stuff. If it's too much of a hassle, don't worry about it. : )
Sorry, I can't post a how-to because I didn't do the mod myself and don't intend to; I just figured out the electrical connections that are needed.
After looking at the schematic I was wondering, given I don't know the draw of one of the coils, is a 1A fuse big enough? I see there is a third line leaving just past the fog light coil.
will the dash indicator be off with the above wiring? (seems the diode will prevent the dash light from luminating unless the driver hits the fog light switch)
One other observation, the fog light switch must be a momentary contact. If the ignition key is turned off (loss of power) while the fog lights are "on" the fog lights revert back to the off position when the power is restored. According to the drawing you should be able to jump out the switch but because the fog lights have to be switched "on" every time the power is restored that tells me that there is a "seal in" contact (or jumper) within the switch that is not being showed.
(I know, I'm rambling) my point is, if the switch was an "open/close" contacts we wouldn't be having this discussion because the fogs light would be on whenever the key was in the on position.
OK, so let's start with how the parts of the lighting system we care about work.
The low beams are turned on manually via the switch on demand, by the DRL relay during the day when the ignition is in the On position, and by the Auto Lights logic after dark when the Ignition switch is in the On position and Auto Lights have not been disabled.
The Fog Lights can only be turned on by pushing the button when the ignition switch is in the On position. This activates an input to the BCM that, if the car is in the correct mode (Ignition On and Lights Enabled) will trigger the relay to turn on the fog lights. The input is a momentary contact that toggles the lights on or off.
In the schematic I drew, whenever the low beams are switched on via Auto Lights or the Headlight Switch, the Fogs come on. They won't come on with the DRL. We'll talk about how to change that in a few paragraphs.
The signal from the BCM that triggers the Low Beam Relay (#38 in the upper left corner) is also used to trigger the added relay. That contact (Relay terminal 86) is switched to ground, so we need to provide a positive voltage for the relay (terminal 85), which we hook to the B+ line on the BCM (a +12 Volt constant supply). The 1 amp fuse is there to protect from any wiring goofs. We won't be drawing nearly that much current; the coils are usually 60 or 100 milliamps apiece.
When the relay is turned on, the power connected to terminal 30 is switched onto terminal 87. This is connected to the BCM output that is used to energize the Fog Lamp Relay (Relay 35, far right, lower) and also illuminate the Fog Lamp light on the switch. With this connection, the fog lights will work as usual by using the switch if the car is on and the low beams are off.
If you want automatic fog lights with only the DRL, connect terminal 86 of the added relay to terminal 86 (under-hood fuse block wire F12) instead of the BCM connection as shown in the schematic.
If you want the fogs on with both DRLs and low beams, the wiring will have to change more. Make the connections as so: Added relay terminal 86 connects to ground. The supply side of the fuse that is connected to Added relay terminals 85 and 30 needs to connect to the DRL relay output (either terminal B2 or A3 on the under-hood fuse block).
Sorry, I don't feel like drawing new schematics to show the alternate connections at the moment.