Interior lights xjs

[XJSDave]

Hi, does anyone know where the location of the relay that operates the 10 sec delay for the interior lights on a 1995 4.0 ltr xjs.
Lights are permanently on, not faulty door switches, disconnected fuse 6 driver’s footwell panel to save battery, 3 relays by fuse box passenger foot well disconnected but not solving problem. ?

[SimonR]

Here's the relevant page in the workshop manual.

Apologies about the oil under the fingernail



Good luck with it!

[davidr]

I suspect that diagram is for the pre- facelift car.
Later cars have a multifunction unit in a similar position on the passenger side that, as its name suggests, takes care of a number of things including the delay for the interior lights

[ptjs1]

Yes David,

that is a pre-facelift workshop manual, unfortunately not appropriate for a 95 car.

Paul

[SimonR]

Ah - my mistake! Although in my defence, that is a page from AKM9063 which says it's for all the 6-cylinder cars, but I've just realised that the final part 9063BB is for the facelift. I guess those pages aren't going to get too greasy on my copy.

Every day is a school day and at least XJSDave has his answer now!

[ng4xjs]

I think I'm in the same boat. Went to start my car this morning and battery completely flat (shouldn't be as a one year old Bosch). Any how put in a spare while on charge. Car started first time but interior lights stayed on. I guess the reason why the battery went flat in the first place but at least found the problem. I too took out the fuse (also the boot interior, don't know why but seemed the right thing to do). I'm guessing it is the module (Interior Lamp Timer Relay ) but never come across this problem before. How do I test it, no idea other than a substitute if I knew what and where.

Any comments/observations gratefully received.

Many thanks
Nick

[almcl]

Sorry, coming a bit late to this, but I *think* the lighting delay unit is the 'black box' on the pax side fuse box mounting panel:

It may also contain the seat belt warning chime, given the speaker grill drillings in the case.

As usual, the Jaguar documentation bears little relation to what is actually fitted but a 1995 update shows this:

which means it could also be the little silver unit with the 3 spade connectors (although the Jaguar Classic Parts website has this down as 'park lamp failure sensor', what?

[ptjs1]

Al,

I'm not sure which is the delay unit, but the little silver 3-terminal unit is definitely a bulb failure unit.

Cheers

Paul

[almcl]

Agreed, Paul. I think the multi function unit is the likely repository for the delay timer, but once again Jaguar documentation is woefully inaccurate.

[davidr]

The multi-function unit on later facelift cars is the black unit arrowed on the post above. As the name suggests, it has many functions which are
1. Seat belt warning module - with the ignition on the warning light in the dash will be lit for a few seconds and there will be an audible chime if the seat belt is unlatched. The chime will stop when the seatbelt(s) are latched.
2. Lights on warning - an audible alarm will sound if the light switch is on (sidelamp or headlamps), the ignition key is removed and the driver's door is opened.
3. Overspeed warning - this only applies to Saudi Arabian market cars and sounds when the car exceeds 120kmh
4. Interior lamp delay - this keeps the interior lights on for 10 seconds after the doors have been closed. On entering the vehicle the light will stay on for 10 seconds but will go out when the ignition is turned on. If the car door is left open the interior lights will switch off after 2 minutes to save the battery. (This may be the function that's causing the issue?)
5 Heated rear window timer - shuts the heated rear window off automatically after 10 minutes
6. Bulb check - operates the brake warning lights within the dashboard for a couple of seconds to check they are operational when the ignition is first switched on.
7. Ignition Key-in warning - sounds when the driver's door is opened and the key is left in the ignition
8. Security system interface - feeds the security module a signal to tell whether the door lamp switches are on or off so it can detect if a door has been opened/closed

The unit does have a diagnostic mode which works like this.
Sit in the driver's seat with the doors closed and the seat belt unlatched. To enter input diagnostic mode do the following:
1. Ensure the lights are switched off
2. Press and hold the heated rear window switch
3. Turn on the ignition whilst still holding in the heated rear window switch
4. Release the heated rear window switch

If the unit doesn't chime that indicates there is no fault. You can now make the following checks
Latch your seatbelt and the chime should sound. Unlatch it and the chime should stop
Open the driver's door and the chime should sound. Close it and the chime should stop
Repeat that with the passenger door
This process naturally checks the key-in ignition switch, ignition input to the multifunction unit and the heated rear window switch.

Now you can go on to check the output diagnostics. If you are still in the input diagnostic mode from above then carry on. If not then repeat steps 1-4 from above. Then turn on the sidelights to get to output diagnostic mode. This will inhibit the inputs. You will use the heated rear window switch to toggle between the various functions. If the chime remains silent then the function is working correctly. If the chime sounds there is a fault.
Press and release the heated rear window switch to toggle through the functions. You press and release to both start and end each function. They are in the following order
Heated rear window circuit
Interior lamp circuit
Seat belt warning circuit
Dashboard bulb test circuit

Switching off the sidelights will de-select the output diagnostic mode. Then switch of the ignition. The multifunction unit will reset and operate normally the next time the ignition is switched on (provided it is not faulty!)
I hope that helps

[Astromorg]

My drawings show there is still an interior lighting relay to check out. The multi-function unit just switches the relay and that puts the lights on and off. Just need to be sure that relay isn't stuck?

[ng4xjs]

Why did I just think this was going to be a simple exchange of the interior lighting delay dimmer module (of which I acquired a fleebay example to test the theory). I'd just assumed that the lights remaining on would point to this as the culprit. I've just not checked the other functions, didn't give that module a second thought. I'll go and check in the morning. Oh well.

Nick

[SimonR]

“Nothing worth having comes easy.”

― Theodore Roosevelt

[ng4xjs]

I did just swap the "dimmer relay" over, to be absolutely sure as I had one to hand. Did the basic checks on the control module and all the functions seem there (clearly not the interior light issue). I think I might just try the door push switches, might be.

Nick

[ng4xjs]

Just curious around the "Multi-function" unit. I've acquired one (which came from a later DB7 (but with Jaguar and the correct part number). But , I think I have failed dismally trying to work out how to extract the plug connection from behind. Did undo the panel that it locates to but so does the fuse box so although more room not enough to see what's going on. From the spare I have at looks like there might be a flap to lift to release on the right side. Having never chamged one previously and not being able to properly look, just not sure, Has anyone else remove one?
Nick