Adaptive Headlight Failure Due to Weak Battery
 

I have my car scheduled to have the battery replaced as it's on it's last legs (load tested), but in the interim I've had a few obviously bad battery symptoms (weird lights on and off, check engine light that records every possible code when connected to a obd, etc..).

But last night, I made the mistake of leaving the radio on, when to start, wouldn't go, but all of the other stuff came on, headlights started leveling while the car was trying to start, it shut off right away lights kind of flickered (started to level)... and I let it sit for a few minutes. Was able to start the car no problem, the headlights came on, and both adjusted horizontally, but just don't go up. I thought it would fix itself overnight after I left it on the trickle charge, to no avail AFS still flashing, and lights still pointing down, but are adjusting appropriately horizontally.

I know this must be related to the battery or something caused by it, so my question is how do I fix this? My concern is even with the new battery, that the issue will remain, did something short circuit? Or is there something I can reset/or have reprogrammed?

I wouldn't fret until the new battery is fully charged and in place. New batteries do not come fully charged so you'll need to make sure that is done before you troubleshoot any of the noted problems.

I'm pretty sure you'll find that the gremlins will all go away after installation and you follow all of the reset procedures (windows, e-brake, etc.).

Reduced voltage requires more current to do the same thing. Hopefully you didn't nuke the modules.

Interesting that the lights on your car would still level horizontally, yet not vertically. I wonder, which of the two tests is normally performed first?

My car has adaptive headlights (they swivel when driving, and they're on the equipment listing), but it only does the vertical test. There's no fault codes, either. My mechanic has since confirmed that my car doesn't actually have adaptive headlights configured! I'm assuming that control module works independently of the rest of the car, which is why the lights still swivel as supposed to when driving, while the horizontal test is missing because the car only requests the vertical test from the module.

Exact same headlight issue
 

DId you ever resolve this? I am having the EXACT same issue with my 2008 XJR.

Five year old thread, and he's not been on for almost four years. Your question will forever be unanswered.

Might get a reply

Last Activity: 09-04-2022 03:53 PM

Vehicle Info - Jaguar F-Type

Have you checked the ground points?
Particularly the one in the front RH wheel arch which serves the lights
It is prone to corrosion and as happened to me can shear off completely
(see photos below before and after fix)

https://cimg0.ibsrv.net/gimg/www.jag...10cde60a5.jpeg
Earth lug in R/H front wheel arch completely sheared off
https://cimg2.ibsrv.net/gimg/www.jag...8a9ae926b.jpeg
Used a short piece of aluminium bar to extend the cable and bolted it to the brake pipe bracket - there is a very convenient spare hole.

OK, I’ll bite… what caused that fresh ground point break? It wouldn’t just split like that on her own; there’s no force on it.

Had exactly the same lug issue on the chassis behind the R/H wheel, totally corroded.When I placed a socket on there to remove the bolt sheared right off as soon as I turned the socket. A number of members have had a similar issue.


https://cimg8.ibsrv.net/gimg/www.jag...edef4d8097.jpg

The earth wires all go to a thicker loom, two of the plastic cable ties had given up so (I think) the weight of the loom was straining the ground stud.