Harvey Posted April 1, 2009 Share Posted April 1, 2009 Hi all, I need a bit of guidance please. I'm trying to do some wiring [front spots and rear fog] and i've got myself confused. My confusion is this: My switch has three points, 'earth, load and supply'. So earth is earth, simple enough. Now is supply the power cable from the relay and load is the splice into the Pathfinder's main wriring loom or is it the other way around? Also, once we have an answer to the above, how do I know which is the main power cable in the main wiring loom? Thanks all Harv. Link to comment Share on other sites More sharing options...
alexrex20 Posted April 1, 2009 Share Posted April 1, 2009 supply is your power and load is your fog lamp. earth is just a ground for the switch. can you be more specific about how you are wiring the fogs? it sounds like you're trying to splice into the original fog lamp wiring, so you can keep functionality of your stock switch, but also be able to override with your own switch...? Link to comment Share on other sites More sharing options...
94extreme Posted April 2, 2009 Share Posted April 2, 2009 there are some good schematics around here but since it's been a while you have some searching to do.. or google.. Link to comment Share on other sites More sharing options...
unccpathfinder Posted April 2, 2009 Share Posted April 2, 2009 you're planning on throwing a relay in right? I don't think you want all the power for the lights going through the switch... Link to comment Share on other sites More sharing options...
94extreme Posted April 2, 2009 Share Posted April 2, 2009 you don't although the factory fogs are wired through the switch, iirc. Link to comment Share on other sites More sharing options...
unccpathfinder Posted April 2, 2009 Share Posted April 2, 2009 my factory fogs had a bosch relay on the pass side firewall but the factory ones always stop working and start poping fuses b/c the wiring is pretty scary if you ask me...i'll be redoing that here as this swap goes on Link to comment Share on other sites More sharing options...
alexrex20 Posted April 2, 2009 Share Posted April 2, 2009 (edited) yes, you should definitely run them through a relay, and use the switch only to open/close the relay. on my four roof lights, i was running them through one relay and 18ga wire. that gauge wire is only rated for 13A and i was running 220W/13V=17A through them. i was popping fuses and the wires were very hot to the touch. you can imagine the damage i'd do if i was running that kind of current through the factory switch... melted wires behind the dash FTL! (i actually wired my lights up with 12ga wire, but the supplied relay connector already had 18ga wire so effectively, the entire circuit would have to bottleneck into 18ga.) Edited April 2, 2009 by alexrex20 Link to comment Share on other sites More sharing options...
jeffrhine Posted April 3, 2009 Share Posted April 3, 2009 I've got three lights on the front with 14ga wire without a relay, and I haven't had a problem with blowing any fuses or wires getting hot. Link to comment Share on other sites More sharing options...
88pathoffroad Posted April 4, 2009 Share Posted April 4, 2009 The switch is what's going to heat up on you. I've had more switches die from not using a relay than anything else. Melted fuses, too. Here's a website with a lot of correct, useful info on how to wire stuff using a relay and WHY. http://www.danielsternlighting.com/tech/relays/relays.html Link to comment Share on other sites More sharing options...
jeffrhine Posted April 4, 2009 Share Posted April 4, 2009 aaahhhh I've had my fogs on for around 4 hours straight, and I'm pretty sure nothing was getting hot. I even popped the hood and checked the wiring under there. I'll prolly through in a relay just incase to save money in the long run. Link to comment Share on other sites More sharing options...
94extreme Posted April 5, 2009 Share Posted April 5, 2009 ^^^ guarantee that your switch did get hot though. Link to comment Share on other sites More sharing options...
alexrex20 Posted April 6, 2009 Share Posted April 6, 2009 aaahhhh I've had my fogs on for around 4 hours straight, and I'm pretty sure nothing was getting hot. I even popped the hood and checked the wiring under there. I'll prolly through in a relay just incase to save money in the long run. it all depends on the wattage of the lamps. if they're less than 65W/ea, then you should be safe(ish). Link to comment Share on other sites More sharing options...
Harvey Posted April 8, 2009 Author Share Posted April 8, 2009 Thanks for your responses folks! I think I might clarify that when I say 'fog lights' I do mean just the single rear fog light and not the front spot lights that are often called fog lights. My switch has a red light built into it hence the three prongs on it. The diagram says, and so I have done... 1 wire from the switch to earth 1 wire from switch to relay 1 wire from switch to main power source for head lamps. It's a legal requirement in the UK that your front fog [not spots for the legal requirement] and your rear fog can only be switched on when your main headlights or sidelights are on. This is why I needed to figure out what was the main powersource. I think I've found it but i'm not 100% sure. The factory wiring is a mess and so too is my attempt at the moment. I just want to see if it'll work and then i'll tidy it up. But I can't test it yet as the car's in bits so I'll have to wait a bit. For the record I'm not trying to override the car's original switch with a secondary one as my vehicle doesn't have front fogs, spots or a rear fog as std hence why i need to fit them and a switch but make sure the lights only turn on with my switch one the main lighting system [side or main beam] are turned on. I hope this clarifies a little. regards Harv. Link to comment Share on other sites More sharing options...
Mr. Pickles Posted April 8, 2009 Share Posted April 8, 2009 I'm not sure on UK wiring vs US, but if you only need to wire them so they are only active when your sidelights (parking/running lights ?) or headlights are on, and if you can't locate a decent source to tap otherwise in the wire harness, you should be able to locate a parking light (this would be a side marker light that comes on before the headlights) near the light source and tap that circuit to activate a relay for your new light install. The relay needs very little power to trigger it on and power the circuit. I would avoid the headlight circuit, though. Link to comment Share on other sites More sharing options...
94extreme Posted April 8, 2009 Share Posted April 8, 2009 it's the same requirement in most states as in UK about the way light switch on/off but i haven't seen one person here yet actually do that. most of my friends have all their lights wired independently of the main lights.. it's just less hassle that way.. none of us ever turn them on in an illegal manner. it doesn't look like you found the wiring diagrams so I'll post one here that I just came across: if it's that important for you to wire in the back light hooked up to the main lights then tap the wire going to the front fogs as that switch is wired that way in the factory. Link to comment Share on other sites More sharing options...
alexrex20 Posted April 8, 2009 Share Posted April 8, 2009 UK fog lights on the rear are red, not clear. they look just like a brake light is turned on, and are designed to make you more visible in the fog to drivers behind you. Link to comment Share on other sites More sharing options...
Harvey Posted April 9, 2009 Author Share Posted April 9, 2009 Mr Pickles and Mzextreme thanks for that. I think I've done exactly what you have both suggested. Also, thanks for the diagram, it's the best one I've seen and is very helpful. Harv. Link to comment Share on other sites More sharing options...
Harvey Posted April 9, 2009 Author Share Posted April 9, 2009 UK fog lights on the rear are red, not clear. they look just like a brake light is turned on, and are designed to make you more visible in the fog to drivers behind you. You're right. But, the back fog always seems much brighter and more neon [if I can use that term]. I don't know why that is though. The back fog is a legal requirement in the UK but doesn't appear to be in Oz [where my car is from]. Maybe intl car makers assume Australia doesn't get fog? Link to comment Share on other sites More sharing options...
jeffrhine Posted April 9, 2009 Share Posted April 9, 2009 haven't installed a relay yet, and I've got 3 daylighters on the front. My switch hasn't even got hot yet Link to comment Share on other sites More sharing options...
94extreme Posted April 9, 2009 Share Posted April 9, 2009 you got a 110v switch on there? Link to comment Share on other sites More sharing options...
alexrex20 Posted April 9, 2009 Share Posted April 9, 2009 i run (2) 100W aircraft landing lights and (2) 55W Hella fog lamps through my stock fog light switch. (at 13V that's 24A of current!) i haven't melted anything yet lol. makes it hard to follow my advice when i don't follow it myself. if my lights have to stay on for a sustained period, i use my roof lights - (4) 55W Hellas on two circuits, each with their own relay. come to think of it, the only real purpose my bumper lights serve me is to flash/blind the oncoming drivers with their hi-beams on... Link to comment Share on other sites More sharing options...
88pathoffroad Posted April 9, 2009 Share Posted April 9, 2009 You're right. But, the back fog always seems much brighter and more neon [if I can use that term]. I don't know why that is though. The back fog is a legal requirement in the UK but doesn't appear to be in Oz [where my car is from]. Maybe intl car makers assume Australia doesn't get fog? Yeah, requirements for lighting in different countries are strange sometimes. Not one car in the US I've ever seen besides a VW Beetle or Karmann Ghia have any rear fog lights. Link to comment Share on other sites More sharing options...
alexrex20 Posted April 9, 2009 Share Posted April 9, 2009 Yeah, requirements for lighting in different countries are strange sometimes. Not one car in the US I've ever seen besides a VW Beetle or Karmann Ghia have any rear fog lights. actually............... you'll notice on lots of jaguars and mercedes and bmw that they have their rear fog light on. it will look like they have a brake lamp that's stuck on. Link to comment Share on other sites More sharing options...
jeffrhine Posted April 9, 2009 Share Posted April 9, 2009 I dunno what kind of switch.. haha my friend bought me a "racing switch" for my spray Link to comment Share on other sites More sharing options...
Harvey Posted April 12, 2009 Author Share Posted April 12, 2009 I have another question regarding this now... My main headlight switch clip was broken so it never staid in it's little socket. So I bough another switch and threw the original away... oh for stupid ideas. Anyway, the original switch had two prongs on the back. My new one has three; earth, relay and power. Given the original switch was 2 pronged, it has two wires; a light blue and a black with blue line. So my question is: which one is power, which one is earth? Also, what do I need to do to make the two wires fit the three pronged switch? Thanks all! Harv. Link to comment Share on other sites More sharing options...
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