Light bar connection for relay - can you help?

[Heroformosa]

Hi all. I'm trying to put a light-bar on my (facelifted) Land Rover Freelander 2. I'm wanting to wire it so the light-bar will be energised when I switch from dipped to full beam (I also want to be able to turn it off altogether to avoid dazzling others, when they're about - but that's an easy job). I expected to be able to take a feed off the full beam bulb to activate the light bar's relay, but this vehicle has only a single bulb for both full and dipped beam coupled with a 'screen' which is activated when the lights are dipped. I've tried testing voltages in the fuse box and in the headlamp unit loom plug/socket, but can't find a circuit with a different voltage between full and dipped beam.
Have I set myself an impossible task? Any advice would be much appreciated.
(I use this car for my commute, often in the dark, on a very remote road in the NW Highlands. The road is very quiet, usually no other vehicles on the 45min drive, but deer are apt to jump out in front of me, and I just want to see the blighters before I hit yet another one - a big red deer stag can make a bit of a mess of the front end of even a Land Rover!)

 

[westward10]

Full and dipped beam may be incorporated into one lamp but the functions should have separate wires at the plug. With the plug disconnected and using a volt meter you should be able to establish the high beam wire.

 

[Heroformosa]

Full and dipped beam may be incorporated into one lamp but the functions should have separate wires at the plug. With the plug disconnected and using a volt meter you should be able to establish the high beam wire.

Thanks Westward10, that's what I thought too, but I couldn't locate anything which might be it. I'm not sure how the 'screen' (as it has been described to me) works, but if moving from full to dipped beam on the lighting stalk simply 'flashes' a brief current which activates/deactivates the screen, rather than maintaining a current which keeps the screen in place, then there will be no difference detectable in the plug between full and dipped beam. That's what I thought might be happening - and if that's the case, presumably it will be no good for activating the light bar relay, which I guess needs a constant voltage to keep it closed. I'm just guessing here!

 

[westward10]

Just been looking at the Freelander 2 headlights and they show separate lamps for high and low beam, no mention of a screen. Is this a standard fit?

 

[Heroformosa]

Just been looking at the Freelander 2 headlights and they show separate lamps for high and low beam, no mention of a screen. Is this a standard fit?

I think that's probably a "pre-facelift" model you're looking at - they moved from 2 to 1 lamp with new headlamps when they facelifted it in 2011.

 

[DPG]

Can you find the wiring diagram on the web? There must be a line somewhere that does the switching.

 

[plugsandsparks]

If all else fails, with a very small relay ( so as not to be detected by the power distribution unit (if there is one) you could intercept the 12V +ve going to the blue lamp on the dash and splice into that. If you could get the wiring diagram for the model you have it may show you some other options to investigate or post it one here and we can have a look.

 

[brianmoooore]

There's nothing new under the sun, as the saying goes. Many decades ago, some cars used a mechanical dipping system, and now it's been revived again for some, although electrically controlled, rather than mechanical rods or cables. Latest LED stuff just dips in zones, which vary depending on where the oncoming vehicle is. Probably works fine on motorways and A roads, but I can imagine it being an absolute nightmare in the lanes where I live.
There's presumably an electrical signal to the shutter/screen and also presumably the blue dash tell tale, as plugsandsparks mentions above, but as he says, the power available might be very limited, and you'd need a solid state relay to go between that signal and the automotive type relay for your light bar.

 

[James]

Auxiliary lighting may be an accessory available from the manufacturer
possibley able to purchase a plug in loom to do the job that integrates with the car correctly instead of having to design a work around?

 

[Heroformosa]

Thanks guys - there's quite a bit there for me to chew over! I'll see what I can come up with. The only wiring diagrams I've found so far are for the pre-facelift, 2-bulb car. Had a chat with a mechanic today who knows the problem and he's looking for a solution too. I'll let you know how I get on, as long as the car isn't written off by a stag in the meantime!