Auxiliary Lights


Adding lights to your Land Rover is really a simple exercise. Below is a wiring diagram and simple instructions to help you complete the task. I mounted the lights on the cross rails of the roof rack. They could also be mounted on the brush guard, or bumper using Land Rover part number VUB500470.
installed switch pannel

The switch can be mounted in dash surround or as I did, removing the ash tray and replacing it with a switch panel from a Discovery I.
Disco 1 switch fog light switch

Land Rover Part # AMR4138 , Fog light switch for series I Discovery.

Pin #1 Three basic options: Use 14 gage wire and 10 amp fuse to protect the switch circuit.
A- Fused 12 volt from cigarette lighter. This will allow the lights to work independent of other lights
B- Fused connection to the high beam circuit . This will allow the lights to work only when the high beams are active. In some state only legal hook up for high mounted driving lights.
C- For fog lights, that only work with low beams. connect to low beam circuit.

Pin #4 Connects to pin 86 on the relay.Use 14 gage wire. When pin 85 on the relay is properly grounded this completes the circuit for the magnet that activates the switch between pins 87 and 30 on the relay.

pin #2 Connect to a dimmed / switched circuit such as tapped into pin two on the cruise control switch. This allows the back light to act in conjunction with other dash lights.

pin #5 Ground for back lights circuit in switch.

pin #3 is not used.

relay for lights


#30 30 amp fused from battery use 14 gage wire.
#87 To lights, use 14 gage wire
#85 To ground, use 12 gage wire.
#86 To pin 4 on switch, use 12 gage wire.

Auxiliary Lamp Wire Diagram


  • Michael Neal says:

    hey, found the parts number for bumper mounting brackets for land rover discovery. its an OEM part #VUB500470

  • What kind of brackets did you use to mount the lights on the cross rails.

  • I actually used an “L” bracket and a flat brace from Ace hardware . Cut off about 3/4 inch from on side of the el bracket so it would not rub the roof.
    Jim Edson

  • Pardon my ignorance but could you please explain what is meant by dimmed/switched power that is attached to pin 2. Eg?

  • That would be any power source that is controlled by the knob that
    dims/brightens the dash lights.

  • Thank you for that. Unless I have totally missed it my D1 doesn’t have a dimmer switch. Would attaching pin 2 to the wire that supplies the light to the cigar lighter have the desired effect?

  • Yes, attach to any dash light.

  • Hey Jim.
    I’m loving this setup. I’m going to try and get it done before Moab. Quick question. Do you have the part number for the Ashtray holder? I’m thinking 4 light switches.
    1. Lights on the ARB, 2. Center Roof, 3. Outer Roof, 4. Work Light (rear).

    Where did you mount the relays? Are you going to be at the Tech Day next weekend? I was going to try and get things wired up there (and service the Tranny and Xfer case).


  • sent you an e-mail. the relays are mounted in the battery box by the jack.

  • Hi,
    Could you tell me where did you enter the cabin with the wire harness from your aux lights?

  • through an existing grommet on the drivers side near the fuse box.

  • Great article! Can the yellow relay with the same pin diagram(Siemens part# YWB10012/YWB10027) be used for this set up?

    Thank you.

  • Having done quire a lot of research on this for the DII, this is a solution I came to as well, but currently still working on suspension.

    This is a good set up where did you route your wiring ?


    PS Website online after winter holiday.

    I used an existing hole in the fire wall on the drivers side. from there to the battery box where I have a fuse block for power and the relays mounted. then up the passenger side window frame. If you lift the rubber bit the wire will just slide under it and into the space behind.


  • Hi well after further research, I will probably go with a combination of what you have done and this While it would be good to have the switches on the dash sides, it is very difficult to get ghe correct switches, and in real world off road conditions, the switches from the DI actually are in a better location.

    I use the stock bumper and not a winch bumper (been there done that) fog lights which work fine with up graded headlight bulbs and I am not fitting a roof rack, the Discovery is limited to weight it can take up top. However I have the stock roof bars, not the G4 type you have, but I like the neat fit mentioned of roof lights due to being in forest quite often.

    So power from battery or engine fuse out let, but separate wiring circuit you have done. I think wiring up the A pillar and then gutter before roof tbc. Could use sun roof seal, then HD mastic, which can work if done properly. Or more drastically drill a hole just inside the front of rear roof bar mounting point, although in theory you cound use the mounting points themselves.

    Let you know how I do. Cheers and have a good holiday however you choose to celebrate it. All the best for 2016.

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