2011 LR4. All of a sudden the lights don't work. When I switch on I get tail lights and dash lights but the headlights don't work. Main or high beam is fine.
So, I looked for a fuse. There isn't one. Not in the manuals or in the guides in the car. There is no fuse for the headlights as in normal cars.
I was told it could be a relay but a) which one and b) how do you remove it since mine ll seem to be almost welded in place.

Mystery and annoying too.
Any clues?

 

Looking at the wiring diagram, the headlights appear to be controlled through a FET instead of a relay. A FET is like an electronically controlled relay - no moving parts, and they seldom fail. They are part of the central junction box and are not, to my knowledge, accessible or repairable separate and apart from replacing the junction box. The lighting control switch provides a low voltage to the headlamp FET, which turns the FET on delivering power to the headlamp.

The problem could be anywhere along the path from the switch to the lamp: Switch - plug to switch - plug into central junction box - plug out of central junction box leading to headlamp - plug into headlamp - headlamp bulb filament.

First thing I would probably do is just check to see if you’re getting voltage at the headlamp. If you are, then your low beams are just burned out (would be quite a coincidence that both go at once, but possible). If no voltage, then I would check the switch to make sure your getting voltage coming out of the switch. If that looks good, you move on to the next plug, which would be the input to the junction box (and any intermediate connections), then the outlet from the junction box, etc. Wiring diagram will be helpful here.

The central junction box is in the passenger side of the cabin, high in the footwell. Any chance you had a leak over there, like a sunroof drain leak? These leaks frequently cause problems with corrosion. That concern aside, I’d say the next most likely culprit is probably the light switch itself.

 

I am going to check the headlamps and need to remove the grille first. The ùanual variously says there are 4 or 6 clips. The top four clips are obvious but the other two are well hidden. How on earth do you remove the grille?

 

Remove the grill by unclipping the top fours clips and pulling the grill OUTWARDS at the bottom and not UPWARDS as the manual says

 

Turns ot that both bulbs had blown at the same time so it is fixed now

 

btw, I had a random DTC code:

B1D01-15 Right Low Beam -
Circuit short to battery
or open
Right low beam circuit
short circuit to power or
open circuit
Refer to the electrical circuit diagrams and check
right low beam circuit for short circuit to power or
open circuit

OPEN means the bulbs are shot. No idea why and no idea why this DTC code did not appear until days after it happened

 

OK. If this DTC is true (open circuit) it implies that the bulb is blown so the circuit is open right? If so, how come LR are not sufficiently intelligent to have a warning light saying the bulb is blown or do they simply think it would be obvious?

 

What electrical condition causes a bulb to blow?
It has two terminals - oner to earth and one to live. If earth shorts to live or live to earth it will not cause a bulb to blow so is it just mechanical shock or old age that causes it?