In reply to a message from Frank Andersen sent Wed 9 Apr 2008:
what about just leaving one door switch on at a time?
I’ll try this, Frank. I’ve been assured it’s mostly likely
in one of the rarely used rear doors, but disconnecting the
switch did not turned the lamps off, but I did only have one
disconnected at a time. I don’t understand this fault at
all, due to my lack of basic electronics knowledge.
I assure you, Christopher - apart from being a ground ‘short’ in the
circuit; it’s whereabouts is the mystery. Not to belabour the point, but
the switch is just a ground, and switches do fail. But you may have to
denude the door panels for inspections as well - the damned thing may be
anywhere…
Incidentally, I spent 3 days virtually stripping down a Renault for a
myaterious ground fault in the marker/direction indicators. It was an
internal short in a two filament bulb - which is hardly relevant here…
You do not mention model year - some versions have a delay relay which in itself may cause problems. And of course a door switch may have failed - though usually they fail to light. The puddle lights are operated only by the door switches…
I have an 1985 xj6. I had a problem once with the puddle lights if you are referring to little red lights. They would stay on. Grounding issue I was told by shop. I have replaced the radio that could’ be it. I remember reeding about grounding issues with these cars. If I remember correctly around fuse panel on drivers side. Any help greatly appreciated. Also I have experience in a book.
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Changing the radio should not interfere with interior lights…
There is an interior light switch - sure it is ‘off’? The main point is still that if the interior lights stays on they have a ground somewhere - normally the door switches. with the light delay relay fitted - the relay is activated by ground in the door switches. Are the door puddle lights also on…?
go backwards from the main fuse. On SII cars it’s #3 (35A). Check the fuse. The lights should go out, if you pull it. All the switches (main interior light switch, door switches) only provide a ground. If you pull them and the light remains on there is an unwanted ground …
And yes, exercising the door jamb plunger switches with oil will help to restore function.
On Series III cars the various interior and door lights are segregated and operate off two different fuses. From memory I think it was the driver’s door switching that was segregated from the others. Or maybe it was the door lights segregated from the pillar post lights. In any case, there are two different “+” voltage supply sources.
The #3 fuse is shared with the power antenna circuit. If the antenna circuit fails and blows the fuse the door lights (at least the ones on fuse #3) will stay on at all times due to some weird back-feed situation. At some point (again, the details escape my memory) Jaguar added an additional diode to prevent this from happening.
I am out of town for a few days but as I remember the puddle light are working correct I will check when I get back in town. Thanks for the help looking forward to driving the xj6 without having to disconnect battery or pulling fuse.
