No Headlights on '14 SD4

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
I

Ivan the Munt

New Member
Posts
4
Location
Norwich
Stopped after a 100 mile journey and on restart found I had no headlights. The green and blue headlight and full beam indicators illuminate as the functions are selected but no headlights show at all. The signature and driving lights are OK. Tail lights OK
There is an audible clunk under the bonnet when full beam is selected which I assume is a relay.

Wassup?
 
Last edited:
Hippo said:
Have you checked the fuses?
Click to expand...
No Fuse for headlights, just 40A fuse for the central control unit or whatever it's called!
Relay swapped.
Switch works as I get green and blue low amd hi beam indications on the dash as selected.
Dipping unit works - audible clunk and 'dolls eye' effect in headlamp lens.
Bulb filament looks fine.

Haven't checked volts at bulb holder or lit bulb up from battery yet.
 
Maybe the output FETs have failed in the CJB, although it would be strange for all of them to fail.

Definitely check the voltage at the bulb holder, and go from there.
 
Is it the zenon bulb only, on both sides, failed?
Or is there more not working like the pack of about 6 LED's each side?
 
Be careful when looking at the highlight circuit when powered. Xenon's use some very high voltages. The striking voltage is many thousands of volts. Enough to kill.
 
Incredibly - totally unbelieveably, both filaments (not Xenon) are visually intact and both are open circuit ie failed with 12v available at the plugs.

How does a bulb fail with the filament intact? How do two do it simultaneously???
 
Ivan the Munt said:
Incredibly - totally unbelieveably, both filaments (not Xenon) are visually intact and both are open circuit ie failed with 12v available at the plugs.

How does a bulb fail with the filament intact? How do two do it simultaneously???
Click to expand...

Because the alternator is out putting too many volts. This can happen with smart charging systems, like that fitted to the FL2. It's normally a sign that the battery is past it's best, and unable to absorb the power from the alternator.

I'd test the battery voltage with the engine running, and see it's under 14.4 Volts, even when held at a fast idle for 5 minutes.
 
There should be a resistance path through the bulb. Its unusual but there have been occasions where bulbs have both failed at the same time due to sudden shock when powered, on other cars. Like hitting bumps hard and the hot wire gives up. Is the number on the bulb correct?
 
You must log in or register to reply here.

Similar threads

A
Combusting wires - one big FUBAR
Replies
7
Views
591
amsthenovice
A
Sierra Charlie
Help required please with query about HDC button
Replies
7
Views
860
Sierra Charlie
Sierra Charlie
I
Not again .... headlights 62 plat puma 110
Replies
1
Views
758
iainmaoileoin
I
T
L322 no illumination on instrument cluster
Replies
14
Views
2K
gstuart
gstuart
J
Classic 1982 Range Rover Headlight / Hazard Issue
Replies
8
Views
2K
Datatek
Datatek
Back
Top