After wondering why I had no dome light in the overhead console I finally realized that the previous owner had removed the bulb. (I'm pretty smart!
So, I buy a new bulb and after squeezing the metal springy tab holders together it finally held it in firmly and voila! I had a working dome light.
So, I thought that the center button between the two map light buttons would control the dome light. But it has no effect.
When I open the door the dome light comes on and goes out after a minute or so. But otherwise I have no control over it.
When I extract and look at the underside of the overhead console I see there's a 3pin connector on the light module that has nothing plugged in. (See photo) Is there something supposed to be there?
Or maybe I'm missing something on what the center button is for.

The backside of the overhead console. Empty connector but no obvious wire from the loom for it.

 

Hi gbmarc,
I don't think that three pin socket is relevant. The connections to the roof console appear to be on a 12 way connector RF3. Almost all the functions of the roof console go through this connector. The master lighting switch is between RF3-1 and RF3-2. This means it is the center switch on the roof console. The map light switches are internal to the roof console. A momentary ground on the lighting switch sends a signal to pin CR1-3 on the Front Electronics Module (FEM). The output from the FEM is on CR10-6. Following the white/black (WB) wire across to the roof console, we can see that it is connected to RF3-3. RF3-9 provides the power to the map lights. The earth wire from the switch and the earth wire from the roof console are the same thing, looking at the designations, but are divided on the diagram to make it easier to read. The reason for the FEM is to allow the dimming function as the lights switch off.
I would check that you get a ground on RF3-2 when you push the switch. If you do, I would also check ground G17, which is just inside the right rear door, probably near the floor. Then, perhaps look at the connections to the FEM especially CR1 and CR10. All of this is in the Electrical Guide. I used the 2006 version, but I think they are mostly the same for this part.
Hope this helps.

Pete M


Lighting switch on roof console connected to FEM

Courtesy lamps in roof console

 

Pete, thanks for the info.
I'll check whether the center switch is earthing or not first.
Regarding the FEM, the connections there look like they are impossible to check unless the unit is extracted from the foot well. I'm in the USA with a LHD car so it's very tight down there.
I also doubt very much that the connections have deteriorated or got damaged because of their location. The only value would be in checking wire continuity to the various FEM connections.

The history of this 2004 XJR which I have only had for 2 weeks is that it came with all the windows stuck down. I found out the FEM is not activating the red Enable wire that goes to to all 4 windows and the sunroof. I removed the headliner and found that someone had cut off the LH sun visor light connection and shorted out the orange supply wire causing it to melt and fuse to various other wires along its route back to the cabin fuse box. (F25 is a 10A fuse and too large for the sunvisor circuit to blow it!!) It was too much work to fix the loom, so I replaced it with a used one but I couldn't access the orange wire as it went down the A-pillar and right side of the dash to the cabin fuse box. So I just checked all the connections from the connector in the RH A-pillar and made sure there were no bad earths or improper wire-melted joinings.
I never did work out why the FEM will not activate the red window/sunroof Enable wire. So, as a temporary fix, I 'activated' it myself whenever the ignition is in at least position 1. I took 12v from the fused side of fuse 7 (Cabin) and connected it to the red enable connecting wire. So now all the windows work.
So, it's not a happy story!!
Apparently the guy I bought it from only had it for about 6 months after inheriting it from the original owner who passed away. Even under the original ownership the car had been investigated for a battery current draw down which had never been found and resolved, and I think it went into the local Jaguar dealer too. My seller had the sagging headliner recovered and somewhere along the line introduced even more electrical problems by shorting out the sun visor lamps.
It's a pity because it's very low mileage and in great condition otherwise.

 

I just ran some quick tests: I tested continuity between RF3-1 and RF3-2 while I pressed the switch. There was none even with the switch depressed.
I then reconnected the console and simulated the switch by grounding out the red wire that goes to the FEM. Bingo! the dome light could then be controlled by touching the wire on and off.
Conclusion: The switch is not working. I have the console out on the bench. The big black button presses on a micro switch soldered into a PCB. Mechanically the center micro switch moves just like the map light switches.
Don't know why something so simply would stop working but that's as far as I've got for now. The whole control board is plastic welded into the plastic case, so not sure how it can be repaired very easily.
Mark


Upper console micro switches under large black activating buttons.

 

Hi Mark,
Good work on isolating the problem. I remember your earlier post now, the headliner with burnt wires etc, that's a very tricky one.
Most of these modules that have circuit boards have little plastic latches somewhere. They are designed to be just clicked together. I wonder if the outer part with the buttons on can be separated from the electronics? Then you may see a way to disassemble it further. I hope you can get to the bottom of it!

Pete M

 

Hi Mark,
good luck with your repairs!
To come back to your original question regarding the connector shown in your picture (which should be 4 pin, actually), the car could be fitted with an intrusion sensor.
It is a one piece module that has two sensors at each end that fit to the holes covered by the rubber plugs that can be seen at the top and the bottom of your picture, and it plugs into the connector indicated by the arrow.
Best regards,
Thomas