alright, since this thread is about lighting and stuff like that... say if I wanted hook up something like roof cab lights (I'M NOT DOING THIS) and wanted them to come on when my parking lights in the front are on, where would the best place be to "splice" them in, or is there another way?

are you talking about clearance lights like on 1ton trucks??? you would need to find the signal wire to the relay for the parking lights... i believe the relay is under the hood by the pass side fender well... but i could be wrong...

Figured i've chime in here, if you did want to add cab lights, or any other light that will come on when you turn your headlights on, You'll want the BLUE/RED wire at the steering colum/headlight switch. That is your parking lights, so whatever you hook to the will be on when your parking lights come on...

Wire up a relay off that wire, and you'll be good to go.

EDIT: Wiring info is from a 2000-2004 xterra, if you want it for a 2005+ send me a PM and i'll let ya know.

alright... you say "relay". that's the thing with the 4 pins labeled 38, 78, etc? How come you need one when you wire stuff up on a car? Whats the point of it? It just seems like a switch that runs off a switch?

well if you run the lights straight off the parking light wires then you will overload the circut and it will cause you problems... by using a relay you are able to make the park light wire a signal wire to trip the relay to make the lights come on and it dosent draw off of the stock wiring...

It uses a low current circuit to control a high current circuit. SO rather than controlling the high side of the circuit directly and running power through a switch which causes a slight drop in voltage your running current and voltage pretty much directly to the load.

Jason's gave a good example too.

i know it did.. LOL i currently dont run a relay but thats only cause im lazy and havent wired in the new relay i have.. LOL

ohh, so would I have to cut right into the wires them selves and get all the right connectors for the relay?

not cut but splice.. LOL

how exactly do you splice into a wire like that? I very scarred to mess with any of the wiring on my vehicle... do I just cut off a small section of the out coating and solder a wire that connects to it and wrap it up in electrical tape? Because that sounds very sketchy to me lol.

They sell lil splice connectors at parts stores for splicing no cutting of wires neccesary just clamp the 2 wires together with a set of good channel locks. These couplings can be finicky though make sure you get them good and tight.

Caleb... really... just go off the fuse block under the hood.. tie your relay to that ..dont splice.. the mod you're thinking is similar to doing the fog lamp mod... but seriously dont splice into it.. if that connection ever fails on you.. you'll lose you're parking lights and your new nifty lights...

Since this thread is about roof light relay, I moved the roof light related posts out of the night rider mod to keep that thread within topic.

Caleb... really... just go off the fuse block under the hood.. tie your relay to that ..dont splice.. the mod you're thinking is similar to doing the fog lamp mod... but seriously dont splice into it.. if that connection ever fails on you.. you'll lose you're parking lights and your new nifty lights...

you would still need to splice into the park lights to get the signal wire... unless you are going to have a switch just for those light??? which IMO would be stupid...

you would still need to splice into the park lights to get the signal wire... unless you are going to have a switch just for those light??? which IMO would be stupid...

exactly, having them come on when my headlight knob clicks once was what I was thinking.

and the only way to really make that work like you want it would be to splice into the park light wire...

correct, the only way to make that work would be to tap into the parking light wires.

As stated, a relay is basically a currect regulator, you'll basically take a 12v current (straight from battery typically), a ground, a swtiched wire (like your PL wire) input, and a switched output (12v+ of your new lights) . When wired correctly, the relay will activate itself from the 12v current of the PL wire, causing the contacts inside to move, to switch 12V current to the Output wire to turn your lights on.

Thats my attemept at a laymens terms of a relay. Electrical is somewhat my specialty as many of you know i work for Best Buy as an autotech doing car audio work.