I suspect this was caused by a faulty LED bulb, but here's the whole story:

I noticed one of my parking lights (the one in the high beam bucket) was dimly lit. This has happened before when one of the LEDs gets loose so I took it out and re-inserted it which seemed to fix the problem. Then upon putting it back into place within the bucket, it must have shorted out because it blew the fuse for the sidemarkers, etc on that side. I replaced the fuse and it happened again, so then I tried switching it with the bulb on the other side and it blew that side too. So I switched it out with a different bulb.

Then I noticed that afterwards none of my sidemarkers, parking lights, or interior lights illuminate when the headlight switch is in any position but "Auto". Not even the dash "lights on" indicator will illuminate. The headlights will turn on when they are in the manual "on" position, but nothing else will light up along with them.

Also, when the headlights are in the manual "on" position" you can turn on both the front and rear fog lights which will work fine, along with their respective dash indicators. But, the general "lights on" dash indicator still will not light and none of the parking/sidemarker/interior lights do either.

So basically everything works normally when it's set to "Auto" which is pretty much where I leave the switch anyway unless I need fog lights. Does this sound like something that would just require a new switch?

 

Anybody have an idea? Or maybe a wiring diagram that would help explain this issue?

 

Check the fuses F97, F63 and F64, all 7.5A in the central junction fuse box.

 

Will do, I'll report back on that later. If not that then what though? Should I look for a new headlight switch?

 

I have an '05 with the newer fuse box design so those numbers don't match up. However, I looked at an older handbook online and saw those numbers correspond to the right/left sidemarker and tail light fuses and the number plate light fuse. The first two are the ones that the defective bulb had blown so those have been replaced and are working. The last one is actually a 5 not a 7.5 according to my manual but it's working regardless. This leads me to suspect that my switch is defective since everything is working normally in "Auto" mode

 

The answer I gave was from the drawing of an 04, sorry. That said, did you have this problem before the lamps blew?.

If you are handy with a test meter, I would confirm first whether you have any power at all along the circuit before buying something that may not be defective in the first place.

 

I did not have this issue before the problem with the LED bulb blew those fuses. And since everything works in "Auto" mode I was suspecting an issue with the switch and not a wiring issue. So if one position on the switch is working normally then it would most likely be the switch, right? Otherwise what else could it be?

 

Hi Evan,
One more check. Switch the stalk to side lamps only and then test whether you have voltage going through the fuses for the side lamps.

If no voltage, buy a new switch.

 

I finally got around to testing a new headlight switch today. Unfortunately, I still had the same issue where the lights only work correctly in "Auto". If it's not the switch or the fuses, what else could it be?

 

Evan, let me look at my diagrams and see what I can come up with for you. I am sure there is something silly that we are missing.

 

Thanks Jim and Chris for the help so far. I looked at some wiring diagrams myself but couldn't really see anything that would explain this behavior besides the GEM now that the switch has been ruled out.

What are you guys thinking?

 

Evan, check fuse F38 in the passenger fuse box. I bet when you blew the fuses F47 and F48 with the bad led bulb, you actually pulled enough current to blow the upstream fuse too. So, I would start there and then lets see what you have. I would say to do an out and out replacement of the fuse F38, even if it looks good. Lets see what you have at that point.

 

Chris you're a genius! I'm literally writing this from the Pep Boys parking lot to express my gratitude. I replaced that fuse and sure enough the old one was blown. Everything is now working properly which is a huge relief!

I'm trying to understand how, if the fuse that supposedly controls the light switch was blown, the lights were all still working properly on auto. Sounds like yet another weird Jaguar quirk.

 

Evan, in short, the AUTO feature of the car bypasses the headlight switch and the one deck of the headlight switch controls where the running lights get their power from. If you want the diagram to see it for yourself, i will send it to you. Once you see the diagram, it will make a lot more sense.

 

Chris, that makes sense. That's probably why I never thought to check that fuse since Auto mode was still working normally. I'm glad you know your stuff!