Foglights as back-up lights

[wheelmanLS1]

I have an extra set of foglights that I picked up from the junkyard. I wanted to wire them up underneath my rear bumper as back-up lights, meaning I'd have to splice straight into the buld socket wires. Is this possible? I mean, 12 volts is 12 volts is 12 volts....

I need to get more back-up light since I'm tinting my tailights and windows in August. I know, I know, the tint has been in my signature for like a week. I just got impatient and wrote it down there.

 

Also, while I'm on the foglight topic, I want to replace my foglight bulbs with something brighter. Stock is H3 55w. Will H3 110w work?(check me on that 110watt).

[jj big shoe]

Check the legallity, but I think it should work fine. I was considering doing something like that as well. Maybe try to french some round ones into the bumper with a three position switch under the dash; off in reverse, on in reverse, and just on.

[Animal]

Two things to consider.

First, which you may not be worried about, is the law. Both BU and Fog lights have output limits. If you go too high on the fog lights, they're considered off-road use only and must be physically covered while on public roads. I believe the standard is set by NHTSA and common among all states. The lenses also have some legal restrictions.

 

If you don't mind chancing a ticket and having to undo all your work....

 

Second, while 12v is 12v, .25amps is not 4amps (actual numbers may vary). Attempting to drive the fog lights with the BU light circuit is not a good idea. You would probably need a relay with a separate power line to drive the fog lights on the rear (note: the factory front fog lights are driven by a relay). You may be better off adding a switch and running some 12 gauge to them.

[GrimGreg]

I have fogs for added rear ligh on both of mine. My 93 is wired like JJ was talking about, but on my 88 I just ran them on their own switch so I can just flip them on whenever I want them (great for tailgaters).

[jj big shoe]

Second, while 12v is 12v, .25amps is not 4amps (actual numbers may vary). Attempting to drive the fog lights with the BU light circuit is not a good idea. You would probably need a relay with a separate power line to drive the fog lights on the rear (note: the factory front fog lights are driven by a relay). You may be better off adding a switch and running some 12 gauge to them.

 

Good point. A bit more work, but it's the right way to do it.

[88pathoffroad]

They're not going to take apart your lights to see how much power the bulbs consume. If they're aimed properly, you shouldn't have any problems.

 

Using the backup light wiring to run an additional 110 watts worth of backup lights is NOT a good idea. Backup lights are only about 24W each to begin with and they didn't run big enough wiring from the factory to compensate for more power consumption, so you'll need to run a new wire from the front to the back so they have their own power feed from the battery.

[Animal]

They're not going to take apart your lights to see how much power the bulbs consume. If they're aimed properly, you shouldn't have any problems.

"They" don't need to take your lights apart. "They" see a light that is brighter than normal and write an inspection ticket. Then "you" have to get the damn thing inspected by someone who may have a meter to check candle power (lums/lux).

Of course, if you are cautious in the use of the brighter lights and don't draw too much attension to yourself, you are less likely to get caught, but when "they" get a hair up their butt (stale doughnuts, cold coffee, whatever), "they" can stop you and do a field inspection just for fun - at least in these parts.

Now, I'm not suggesting anyone sholdn't do it, I've been looking for brighter fogs myself, just wanted to present the risks.

Edited July 27, 2005 by Animal

[Mookie]

I used tractor lights for my backup lights. Was going to use fogs. I have them wired seperately with a relay. That way when I'm camping, they can be used to help me setup in the dark. They also come in handy when you come across an accident scene in the dark...

 

Here in Western Canada, if you use fogs or other lights as auxillary backup lights, they fall under the category of "Docking Lights". Probably is the same in most Provinces/States?. Basically, most Semi- trucks have auxillary backup lights that they use when backing up to the loading docks. Keep them aimed right and they don't even need to be covered. They can be high wattage too. You can only have two though.

[Animal]

Knew a guy, years ago, that had a PU with aircraft landing lights for backup lights. He swore it would melt the paint off anyone tailgating him - that would definately draw the wrong type of attention.

[wheelmanLS1]

If I use a relay, can I make it so it comes on and off with my other back-up lights? I've never wired stuff with a relay.

[Animal]

Yes. I'd have to look at the wire diagram to see if the bu switch goes to ground or +, but in either case you'd just wire the relay's coil in-line (parallel) to the existing lights, or in place of the existing lights if you're eliminating them. Then run a heavy gauge wire (12 should do it) from a fused line off the battery to the relay's operating contact and hook the lights to the normaly open contact. Something like:

 

--exisitng bu wire---> relay coil <----ground

battery + -->fuse<--> relay contact | relay n.o. contact <--->lights(2)<---ground

 

Put the fuse up near the battery and the relay back by the tail lights.

[jj big shoe]

the12volt.com is a pretty good reference site for stuff like that. Take a look at a few relay diagrams they have and you'll probably be able to figure it out. Good luck.

[snosnk]

If I use a relay, can I make it so it comes on and off with my other back-up lights? I've never wired stuff with a relay.

 

Thats what I did. I used the power lead going to my backup lights as a trigger for the relay. I grabbed power from the distibution block for my amps to run the lights. I also ran a switch leg to the front so I can turn them on with a switch. I wired an led in series with the switch so that I would know when they were on.

 

Drivers side backup light.

 

 

Switch with led