just got my 2010 prius with OEM foglights. I was wondering if there's a mod that I can just turn on my fogs without having to also turn on the headlights. tried searching, but couldn't find anything. If there's already a post, please redirect me there. Thank you!
Jimbo, I was going to post the same thing, but you beat me to it. As for the OP's question: yes, you can modify the lighting to do that. I haven't seen any instructions posted for the Gen III. Tom
Driving lights are essentially reduced intensity headlamps intended to make cars easier to see during daylight hours. Fog lamps are specialized lights intended to light up the road immediately in front of the car in low visibility situations, usually located low to minimize back scatter. Tom
^^ A lot of cars use the fogs as DRLs. I've seen Acura SUVs all the time with them edit: Sorry forgot to post a possible wiring mod. There should be a wire that sends a signal to the relay that the headlights are turned on. If cut and wire that into the fuse box where there's a 12v constant when the car is turned on, then you will be able to independently run (via switch) the fogs without the headlights or parking lights turned on.
I do not know if this helps or not but the OEM foglights that I purchased from the Prius Chat Shop will work with either the parking lights or the headlights on.
On my V, I have the stalk switch on my steering column. When the headlights/parking lights are switched to off, the foglights are forced into the off position. If you turn your parking lights on, you can then rotate the foglight switch and turn them on, however in the US they will not come on until the headlights are on. I rewired my foglights to work with the parking lights, and not just the headlights (and they'll stay on with the high beams). I just cut a wire the foglight signal wire and spliced it over to the parking light signal wire. I took some pics of it but I can't find them so I'll have to take some new pics later. If you have an aftermarket kit that you installed yourself, more than likely you'll have a dash switch for the foglights. You can wire that up any way you want, so the foglights can on at any time. What I like about the factory stalk switch is when your turn off any parking or headlights, it'll force the foglights off. But then you can still make a dash mounted switch to turn off on its own when you shut off the car.
I believe this varies by state. I believe Wisconsin and Illinois, for example, allow fogs on with no other lights. I'm aware of no federal regulations on this. (Please point me to them if you are.)
I know when I moved to Connecticut in '97 they tested my fog lights to make sure they went off when the headlights were turned off. But the high-population states have a lot of rules that other states don't have (including extensively testing cars being registered), so I don't know how common this is.
The OEM fog kit from PriusChat is linked to the parking lights (so unfortunately, it'll stay on during high beam operation so the driver will have to remember to turn it off or risk getting a ticket for too many lights). However, it also switches off when the headlight stalk is in the OFF position.