The radio just stopped working while driving and of course the aerial stayed up. There was a 35a fuse on the l/h fuse box marked interior lights etc. Replaced it and brought the aerial down then it blew again. Is the radio dead short? The passengers side interior door light is also on with all doors shut.
Finally fixed the fuel problem now this. Any ideas? Can’t find any inline fuses in the boot either.
Col
Sorry it is on a 1983 VP XJ6
After looking through the achives I see people with exactly the same symptoms but I couldn’t find what the fix was. Can anyone remember what it was?. Need to get a pocketful of 25a fuses tomorrow before I start.
Col
Try removing the Aerial relay (inside the trunk by the aerial motor) and see if it makes a difference.
Do the same with the radio.
More likely though, I think there is a short somewhere on your passenger doors cables, most probably where they flex between the door and chassis.
With the door open you can separate the rubber boot and inspect.
Aristides
Thanks I will try take tomorrow after obtaining more fuses.
Col
The interior lights and antenna coincide in a strange way. Some stay on, more or less dimly, when the antenna acts up.
The antenna is powered by a (purple?) wire from the radio and also has a fuse, I think aerial. The relay is a good start; I fear I forgot what it was in my case but I guess it was a short.
Antenna and relay are with the fuel pump in the spare wheel tray.
David
Disconnected relay to aerial all connections and the is still a dead short across the fuse. Took the bulb out of the l/h puddle light and there is still dead short. Now I need to remove the radio and look for the aerial fuse and shorted wires?
Col
Further investigation proves no fuses to radio blown, but solid brown wire to “ puddle “ light passengers side has 12v on all the time!
So with relay for aerial completely disconnected, puddle light disconnected, radio disconnected, there is still a short on the fuse.
Does that fuse feed anywhere else? Or does it have to be a short in the wiring somewhere?
Col
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This should not be a 35A - it’s rating is spec’ed as 15A, Col…
‘Left’ hand fuse box is the ‘main’ fuse box on LHD - and #3 fuse is indeed the aerial and interior lights, but is supposed to be 15A.
Questions arising; that a ‘wrong’ 35A blows means a short - but some PO may have added unknown items to the circuit and upped the fuse to 35A. Which is not recommendable - too high fuse rating may cause wire burnout, and shorts.
Further; the radio itself is originally fused by a separate 2A inline fuse behind the radio - the aerial is separately fused by #3. While a blown radio fuse, or shorted radio, may blow the radio fuse will stop aerial working - it will not blow the aerial fuse. Unless a PO have done something, which will complicate matters; repeated replacements of the fuse is ill advised before the something is sorted. As a minimum; use only 15A fuses…
Remove the #3 fuse and test the radio - it should work, though with the aerial down may not have good reception. However; if the radio does not work with #3 fuse removed; you have non-standard connections…
That is as should be, Cal - plain brown wires are always powered from the battery - and are unfused. Also, puddle and interior lights are designed to light up with any door open. That only one puddle light lights up with the doors closed implies that the door switch is no the cause…
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Have you checked if there is power on one side of the fuse holder - it should have 12V from brown wire. And with power on an ohmed circuit; resistance readings are meaningless…
Frank
xj6 85 Sov Europe (UK/NZ)
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How can the radio be tested, out of the car?
The fuses to the radio are ok. But no lights when on.
As far as I know there are no modifications to the car in any form.
Using test lamp across the fuse there is a bright light, indicating a short or high current draw. If , as was the case , the radio was removed, the aerial relay was removed and completely disconnected the it just struck me that the fault can only be in the interior lights, any of the six or seven if the reading / map light is included as that is the only things still connected to that fuse.
Am I on the right track??
Col
Ok radio out and disconnected, all ten interior lights have the bulbs removed and now the short across fuse #3 is gone. Tomorrow I’ll have the radio checked and if it is ok I will reinstall. Too cramped in the garage at the moment …
Col
True!!
Frank beat me to it. One of the four puddle light switches in the door posts is grounded. Or the black wires attached thereto. One by one remove and disconnect. See if that puts out the puddles…
The switch in my driver door went bonkers, but the other way. Open. I’ve a good switch via Paul Novack. And whenever it warms up
around here, i’ll switch it out, Weak pun!!! Purely accidental!
Carl
Carl
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One possibility is that one of the bulbs have fused, Col, causing a ‘short’. Or even more remotely; something wrong with one of the bulb holders - shorting with the bulb in place…
The test lamp reacts to current flow - whether it is drawn by a short or ‘legitimate’ current drawn by items ‘on’. Varying the size of test lamp will indicate the amount of current drawn of course; a 100W head lamp draws around 8A - a 15W is fully lit around 1,2A.
Did you actually check if any lights were lit with the test lamp lit? If not; with lamps unlit, nominally the switch involved would prevent power to the lamp circuits. Of course, a plain short will nominally leave everything in the circuit powerless…
The step now is to keep the test lamp connected while you reinstall/reconnect everything in turn. The test lamp will give a visual indication when you touch a tender spot.
If/when it does; you can check current drawn with an ammeter - the usual way to possibly identify a culprit. Perversely, with a short the ammeter will blow a fuse… 
Frank
xj6 85 Sov Europe (UK/NZ)
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Ok tomorrow is test day. I was relieved to find the “short” was gone when the lamps were all removed so I never looked to see if any lights were on. Just slept better but had a planned day out today so tomorrow back into it.Thanks for the detailed explaination of the tests. Results tomorrow.
The radio has gone to technician for a quick check, also back tomorrow. I wonder what the world will bring me tomorrow.
Col
Radio checked out ok. Pulled the aerial relay apart and bench tested it. Reinstalled all and radio, aerial and interior lights except for the drivers side puddle light. I will pull the trim off tomorrow and see if I can rectify.
Correct fuse seems to be holding so here’s hoping.
Col
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The ‘unexplained’ disappearance of the short is a fly in the ointment, Col…
However, if it reappears, the fuse will do its job with no damage done - you just have to start over…
Have you tried disconnecting the wire to the door switch…?
Frank
xj6 85 Sov Europe (UK/NZ)
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I almost typed that. but, then thought again. Is the driver side door switch only related to the driver puddle light, or to all???
Best thought, Get out the Jaguar S57 schematic. track the puddle light circuit on it. then the page showing the location of components. That might produce a clue as to where a hot wire touches metal…
Nearby parts that move would be a clue as well.
Carl
All, but antenna and puddle lights are interconnected. Fuse burned, and some lights stil come on dimly.
It can be a wire shorting; but the operation of the switch only grounds the lamp, no?
+1 on the schematics.
Ditto:
The last time I had a door switch out, I’m sure the wires were black, denoting ground. logical as well… Not that jaguar ever did anything that defied logic!!!
Carl
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But sometimes the logic is elusive, Carl…
The single wire from the switch connects to a circuit that connects interior and all puddle lights together - any door switch grounded will light them all, as David remarks.
Of course; puddle lights are only relevant for door used to enter/exit, but the interior light is relevant whichever door is opened. There is no way a single door switch can do both independently - and two switches at each door to do this raises cost, with no comfort gain…
All lights are constantly powered, so if the one puddle light lights alone with the door closed; there is a ground somewhere that grounds only that lamp without grounding the others. A detached and grounded connector, ‘somewhere’, springs to mind - but ‘where’ does not…
Frank
xj6 85 Sov Europe (UK/NZ)
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