With the headlight switch in the automatic position, the lights will sometimes not come on, or when I run over a bump, they will go out. I have found that tapping on the sensor housing (see attached photo) or sometimes twisting the mirror will make them come back on - until the next bump. I've taken it apart and reassembled it. I did not see anything obvious like a loose or broken wire.

Any suggestions for a fix?

Oh, and my car is a 2005 XK8.

 

Hi
I went through this issue a while ago and posted some stuff on one of the forums. The system seems to work on a switched earth from the sensor to activate the lights. Basically if you remove the interior overhead light panel and find the wire (sorry can't remember the colour) that goes to the sensor. Touch the connector with an earthed wire and with the switch in auto and ignition on the lights should come on. Mine did and this proves the wiring to the switch and from there to the control unit. This proved to me that my sensor is faulty and I couldn't pluck up the courage to remove the mirror from the windscreen so decided to live with it..
Good luck
Pete

 

Do you have HID lights? My HIDs would flicker and a bulb replacement resolved the issue.

 

I'm wondering if there is a way to acquire a new sensor, or does the entire mirror assembly have to be replaced?

The headlights don't "flicker". They work fine when turned on manually. There just seems tog be a fault with either the sensor or the circuit that controls the automatic setting.

 

On my 05 the lights took forever to turn on at dusk. Quite by accident, I found that moving the mirror ever so slightly turned them on. I was lucky, found an 06 XK8 at a local Pick n Pull and bought it's mirror. That fixed it.

 

Had same issue, auto on/off worked great. but then lights would go out, and I'd give the mirror a little squeeze, then they're back on.
What I did was use some cyno glue, at each corner of mirror, in the crack separating the front and back plastics, and squeezed each glued corner while it cured. It fixed the prob, somehow.

 

As I recall it is the yellow wire grounded for auto headlights. I published the color in a post a few months ago. I'd look it up for you but am on a phone. If you need the color search my posts, think I even put a subject title that'll ID it for you.

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OK back at PC here's the post:

I just finished working with an owner on jaguar forum. He faced the common question: my auto headlights do not turn on. Is my mirror broken (it houses the opto Electric sensor), or is the switch faulty.

Turns out that if you pull the overhead console down and expose the wire harness from the mirror, you will bypass the mirror sensor if you ground the yellow blue wire. Iow, if you do this and the lights work normally [switch=auto; ignition on] you proved the fault is in the mirror.

I am posting this for all of our future reference. My thanks to Pete on the other forum. John

 

Sounds like a common fault. Guess I need a new mirror.

 

I think I paid $15 for the 06 mirror at Pick n Pull. Its been faultless for months. I simply pushed down on the mirror parallel to the windshield and it slid off the mount. I then slid the new mirror up parallel to the windshield till it clicked onto the mount.

 

I have the opposite problem. When in auto my lights never go out, even in broad daylight. If I turn them to off, I get the dash warning telling me my lights are off. Again, even in broad daylight. Am I looking at the same resolution? Thanks