foglight wiring

[timmy0tool]

i received a set of foglights without the necessary harnesses. i didn't want to purchase an aftermarket wiring kit as it will clutter up my engine bay. i needed to come up with my own wiring schematic. after a lot of research, i finally came up with a proposal seen below. however i have a few questions relating to it.

can i place the foglights in parallel as shown? running at 12V and 55W each i calculated, using the ideal values, that the resistance before the in-line fuse is 1.31ohms. at 12V this means it will take 9.16amps of current to power the lights. can a single 16 gauge wire handle that load? can the 12V source in the kickpanel fusebox be enough to power the lights?

as of this point, i lack having a switch so i made two options in my diagram. temporarily, i'm going to wire with the "without switch" option. is my SPDT relay correctly hooked up? again will there be enough current through the wires? how does my "with switch" option fair out?

i know there are a lot of quesitions asked so answer them as best as you can. thanks in advance.

[olivrooom]

Holy crap Tim! You're really doing your homweork on this one huh? Hahaha! Let me know how it goes cuz I'm in the same situation as you. Still trying to find foglight switches for both of us.

[timmy0tool]

anyone else have anymore input? i'm looking in your direction cpmike. i need to know so that i can install these bad boys.

[Accord SiR]

They do run in parrellel sequence. I haven't installed that part of my wiring harness so I will get you a picture of that section of the wiring harness.

[cp[mike]]

carlos is right, they do run in parallel, and the diagram you provided looks to be correct. (yes, the relays are hooked up correctly).

for a 0 to 20 amp circtuit, for 0-4 foot runs you should use 14g, and 4-7 foot run should use 12g. more on this below.

now, i dont recommend using the under-dash 12v pin to power both foglights, use the battery. hook up a line directly to the positive terminal, run it through youre fuse, and run that right to the 30amp relay. the relay and fuse i would say should be in the front of the engine bay, somewhere close to the fogs, so its a short run from the battery, thru the fuse, thru the relay, to the + of the foglights. then, you only need to run a single wire (any gauge) from the coil of the relay (86 like u pictured) to the switch inside of the car.

now since that would be a short run, battery->fogs, 16g wire would be fine. technically insulated 16g wire should be able to handle up to 22amps without badly overheating, if im not mistaken... and if you look at teh stock wiring, its smaller than 16gauge.

[timmy0tool]

thanks for the confirmation on the fogs running in parallel. yeah you're right about the stock wire being smaller than 16g. i'll be sure to directly wire up the fogs to the battery terminal and keep the fuse and relay under the hood. dang mike what would i do without you. i'll have burned up wiring that's what. THANKS a bunch for the input. now i can start on it.

[ChIoVnIdCa]

Wire is cheap why skimp out on the size. If your going to use 16awg though dont use the 30amp fuse (It will offer little protection in preventing the wire from buring out). Use a 10amp or 15amp fuse.

[timmy0tool]

Originally posted by ChIoVnIdCa
Wire is cheap why skimp out on the size. If your going to use 16awg though dont use the 30amp fuse (It will offer little protection in preventing the wire from buring out). Use a 10amp or 15amp fuse.

yeah i know wire is cheap but when i wired my alarm, i prewired my fogs (a single wire from the front of the car to the cabin) using 16awg unaware that it might not be adequate to hold the current. what i plan to do is just what mike suggested. use that wire for the switch and simply do the rest of the wiring under the hood. thanks for the info about the fuse ratings. i'll go ahead and try a 10amp. if that doesn't hold up, i'll go to 15amps and so on. i don't think the fogs will use that much current though.

[timmy0tool]

here is the revised version of the diagram above. tell me what you guys think. maybe this thread should be a stickie .

[cp[mike]]

new diagram looks good, and i might just want to mention that starting from the rear end of the car, moving toward the firewall, the four 12v power pins in the driver side fuse box are:

1 - accessory
2 - ignition
3 - parking lights
5 - constant

so the "switched prong" that timmy is talking about is the third pin to the right, #3. this will only allow the fogs to be on when the headlights are. as another option, hooking up to the #2 pin will allow you to turn the fogs on any time the car is running.

[jdmkid]

is a relay nessicary

[AccordWarrior]

new diagram looks good, and i might just want to mention that starting from the rear end of the car, moving toward the firewall, the four 12v power pins in the driver side fuse box are:

1 - accessory
2 - ignition
3 - parking lights
5 - constant

so the "switched prong" that timmy is talking about is the third pin to the right, #3. this will only allow the fogs to be on when the headlights are. as another option, hooking up to the #2 pin will allow you to turn the fogs on any time the car is running.

Is that for OEM wiring Mikey? So I could bypass and get my fogs on whenever?

[cp[mike]]

Is that for OEM wiring Mikey? So I could bypass and get my fogs on whenever?

i dont know how the OEM wiring harness is tied into +12v, ive never dealt with it, i wish i knew. all i know is that when youre installing an aftermarket wiring harness kit, you use those fusebox jacks, giving you the option to decide when you want the fogs to be able to be turned on.

is a relay nessicary

absolutely.

[jdmkid]

QUOTE]absolutely.[/QUOTE]
damn knew i should have payed attention in auto class o well cant be that hard to figure out

[dwf137]

Since fog lights need to turn off when you flip on your high beams, could you tap the wire for the blue light on the dash and run that to pin 87A? that would shut off the fogs when the high beams are turned on right? or am I getting this whole thing wrong?

edit.. nevermind. i figured it out...