[xj-s] Radio memory feed fuse, where is it?

Just doing the radio, towards the end of my rebuild. It is
not the original one so I am having to connect it to the car
loom via a DIN plug. I have identified the aerial feed and
the live input from the ignition switch. Also identified the
speaker wires.

Question: There is a purple wire (car is 1985 V12 coupe)
which I THINK is the ‘‘always live’’ wire that keeps the
memory going. Of course I did not know that and accidentally
earthed it producing sparks and then nothing! The purple
wire is the same colour as the feeds to the courtesy lights,
so I guess that it comes from there as they are always live,
but there must be a fuse somewhere that I have burnt out.

Problem is I do not know where it is. I guess it is one of
those inline jobs so could be anywhere. I have looked under
the skislope but the purple wire disappears into the loom,
so no obvious fuseholder there.

Any ideas gratefully received.
Greg–
UK spec 1986 XJS V12 HE
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Hi Greg,

Do you have the Electrical Guide for the 87 & prior model?
Unfortunately that one is NOT available online, but it is in the JDHT
CD.

It does NOT show any Purple wire related to the radio connector. What
it does show is a 6-pin connector with one pin unused. The wire colors
for power into the radio are: (1) Red, which is the constant battery
power feed via a 2A inline fuse; (2) Yellow which is the main power
feed from the radio relay, via a suppressor on some models; (3)
Red/White which is from the panel light rheostat, for radio face
lighting; (4) Black which is from the suppressor on some models.

There is a 5th wire, White, which is a power out providing signal to
the antenna delay relay when the radio is on.

If you find that your vehicle has wires of those colors to the original
plug, try a voltage check with the key off and also on on the Red and
Yellow wires, and let us know what you find. There is a Brown wire to
pin 30 of the radio relay that supplies battery power via a 20A inline
fuse.

George Balthrop, Clifton, VA USA
89 and 85 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: gregory wilkinson-riddle gwilkinsonriddle@orange.fr

Question: There is a purple wire (car is 1985 V12 coupe)
which I THINK is the ‘‘always live’’ wire that keeps the
memory going. Of course I did not know that and accidentally
earthed it producing sparks and then nothing! The purple
wire is the same colour as the feeds to the courtesy lights,
so I guess that it comes from there as they are always live,
but there must be a fuse somewhere that I have burnt out.

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In reply to a message from George Balthrop sent Mon 2 May 2011:

George, thanks for your reply. The colours I have do not
tally with yours, though basically the functions do.

I do not have the pre-1987 guide. The only diagram I have is
from the Haynes manual, which does not show all the wires.

What I have (and have verified) that agrees with Haynes is:

White/pink ignition feed (live when ignition is at position
1 and run position 2)
White/pink 12V output to power aerial relay (live feed to
this and the aerial works)

In addition I have (not shown in Haynes diagram):
Four x 2 wire speakers (obviously)
1 x red/grey (this was not used before so I am not worried
about it).
1 x purple - which is the problem one. This must have been
the continuously live feed as the previous radio had memory
stations and no other wire has a non-ignition feed;

The loom is standard for the model and year and it all
worked on the old radio. So somehow the feed via the purple
has been shorted by me. I guess there is a 2 amp inline fuse
somewhere (as you mention below) but where?

Hope this may help

Greg–
The original message included these comments:

for power into the radio are: (1) Red, which is the constant battery
power feed via a 2A inline fuse; (2) Yellow which is the main power


UK spec 1985 XJS V12 HE
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

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Hi Greg,

The JDHT Electrical Guide for 87 & prior models, “Late Radio” shows the
2A inline fuse and radio relay as being located under the ski slope or
black console cover, while the 20A inline fuse that powers the radio
relay is located in the radio enclosure, just forward of or beneath the
radio unit.

George Balthrop, Clifton, VA USA
89 and 85 XJ-S Coupes; 89 XJ40 VDP-----Original Message-----
From: gregory wilkinson-riddle gwilkinsonriddle@orange.fr

The loom is standard for the model and year and it all
worked on the old radio. So somehow the feed via the purple
has been shorted by me. I guess there is a 2 amp inline fuse
somewhere (as you mention below) but where?

// please trim quoted text to context only

In reply to a message from gregory wilkinson-riddle sent Mon 2 May 2011:

Have a look at this post to the photo album I did some time
back, it may have the info you are looking for:

http://www.jag-lovers.org/snaps/snap_view.php3?id=126690249

or: http://tinyurl.com/29x73ey--
The original message included these comments:

has been shorted by me. I guess there is a 2 amp inline fuse
somewhere (as you mention below) but where?


84 XJS, 89 XJS, 89 XJ40
Santa Barbara, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

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In reply to a message from WayneC sent Mon 2 May 2011:

Many thanks to all concerned for the information. I think
that UK cars had a different wiring colour scheme from the
USA one, at least concerning the radio wires. The solution
has been found as follows:

With help from Grant Francis I found that the purple
continuous feed to the radio, the one I shorted out, came
from the cigar lighter circuit. This circuit I THOIGHT I had
tested, but I was fooled by the illumination working. The
cigar lighter fuse itself was labelled as ‘‘fog lights’’ on my
car as it had a LHD label inside the main fuse box cover -
this was clearly a factory error as it is the original
cover. The only difference being that on RHD cars UK spec,
this fuse is the cigar lighter.

Changed the fuse and the cigar lighter worked and so did the
continuous feed to the radio!

So on UK spec V12 HE cars pre-1987, the radio has:

  1. Pink/white feed via a 2 amp fuse just behind the radio,
    ignition activated,
  2. Pink/white 12v wire FROM the radio to the aerial relay to
    trigger that relay when the radio is switched on,
  3. Four speakers with 2 wires to each,
  4. One purple wire giving 12v continuous feed for the radio
    memory, fused from the cigar lighter fuse
  5. One grey/red wire that I do not know what it does but is
    not needed to run the radio and the cassette, as it was
    taped off! If anyone has any ideas about this one I would be
    interested to hear from them.

Thanks again to everyone who helped

Greg–
UK spec 1985 XJS V12 HE
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

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