i just got my S5 bumper installed and i want to hook up the fog lights. threre are two wires off of the lights and two wires of of the stock switch. i need to know which of the fog light wires is the ground and which is hot? i plan to run 12v to each hot wire and then each grd to the switch then the switch to the chasis.

anyone who has already done this or knows which is grd on the light houseing let me know

thanks,
john

 

it doesnt matter which fog light wire you use since incadescent bulbs work in either direction, but the convention is the darker color for ground. dont run the 12v wires directly to a switch as the switch is probably not made for that much current. youll need to use a relay.

 

Yup a relay and a voltmeter so you can tell which one's hot which one's ground.... you can even use some cheap 12v bulb from pep buys or something if you can't afford a voltmeter, but that'll just tell you if there's current and not which one's hot... But rockshox, is right usually Dark = (-); Light / White Red etc.. = (+).
You could check with the bulb, if you wire it from one wire to the chassy and it lights you found your + if you don't get anything you found yuur -

Relay is a must, in the switch situation.... the Foglight kit should come with one... or else radio shack sells some automotive relays... (If you need help with how they work ask ! )

-DC

 

so its not a grounded switch?? yes please explain the correct way to wire my 89-91 fog lights i have the lights, the brakets and the switch.[i bought the switch and lightrs seprate]

thanks for you help

 

ground one wire from the fog light. connect the other fog wire to one of the relay contacts. connect the other contact to positive voltage. connect one side of the relays coil to ground. connect the other coil terminal to the switch. connect the other terminal on the switch to positive voltage that goes off when the car is off.

 

hmmmm......sooo should i hook both of the fog lights to the same prong of the relay??

and also.....if at all possible could sumone post a picture diagram, not the brightest here , also......could you use the number of the prong....just so i dont blow anything up....heh

thanks muchly,
john

 

bump

inoo im kinda asking for idiot protection, but hey.....i can't blame me......heh <me

 

There's a wireing diagram on most relay boxes, or on the houseing itself...
In escence a relay is nothing but an electro-magnet that closes or opens a switch so there's two cuircuits...
1 the switching cuicuit... (Low Voltage) (Trigger) and two the high voltage that you want to send to the device beeing triggered (Fog Lights)

Typically you run a "Hot" + wire from the Battery to the relay and from the relay to whatever you're triggering.... with the relay beeing the interruptor... of current...
then wire the switched voltage... (Find something that gives you current like the voltage from your stereo, but is only on when the car has a key in it...
run that to the switch, and then the relay to trigger the relay, to feed the headlights.... so when you look at it as two "Pipes" of voltage where one triggers the other you'll be allright... the switch you bought just controlls the flow to the relay, that way you can turn the lights on and off even though the key is in the ignition....

BTW a better source for your switched voltage is the ashtray light in an FD, and something similar that is only on when you turn on the headlights... Ignition would be good for daylight running lights if that's what you were going for...

-DC

 

I have a quick question.. Does all FD pre-wired for OEM fog lights?? or do you have to run the wires??

 

:edit:

damn server........double post

 

first off thanks loads to DCrosby for the explination.

i wanna make sure ive got this down right before i do anything, so i drew up a diagram to the best of my own knowledge,......if its rediculious please let me know. im not an expert at wiring,.........or anywhere near it!

i have a few five prong relays and a three, i should be using the five right?

 

oh yeah and i forgot to grd the other side of the fog light.

 

anybody?, just tell me the numbers of the contact i should use for each thing?

ino alot of you guys know, just about all of you know more about wiring than me !

 

*d0t*.....*d0t*..............*d0t*

anyone.....seriously .......im not clear on how to do this yet, and i don't wanna do it if im not sure.

any help??

 

um 12v goes to 30, foglight to 87, switch goes to 86, ground 85. other terminal on the switch goes to 12v. other terminal on the fog light goes to ground

 

thanks very much but isnt the stock switch a grounded switch......in other words shouldn't it go from
86-----switch-------grd

from Scott 89t2 i got;

 

Yea that sounds right, sorry I hadn't checked this thread in a while... PM me if you have further questions...

As to the FD question... I'm not sure... I'm almost positive that the PEP had an option for fogs, and all of the touring models i've seen have them / a stock harness... but I'm not sure weather R1/R2 had it as an option .....