Jaguar XJ-S. Manual - part 166

 
 

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If cheap is what you’re looking for, Wal-Mart and AutoZone offer “Blazer” driving/fog light kits.  These sets are 
amazingly cheap -- barely more than the value of the H3 bulbs included.  If you break a lens, the replacement lenses are 
for sale right next to the light kits on the rack! 

If you’re looking for good fog lights, the systems using the dichroic filters described by Daniel Stern on page 655 are 
the way to go. 

When installing fog lights, be sure to provide a suitable ground connection -- directly to the base of the bulb itself, if 
possible. 

 

FOG/DRIVING LIGHT BULBS:  Fog lamps or driving lamps are usually fitted with either H2 or H3 bulbs.  H2 bulbs 
appear to be mounted on a metal blade while H3 bulbs have a circular metal base with two notches, one rectangular and 
one semicircular, and a short wire attached with a spade terminal at the end.  Both are typically 55W. 

 

FOG/DRIVING LIGHT BULBS -- MORE POWER:   100W H2 bulbs  are available from J. C. Whitney.  100W H3 
bulbs are available at many auto parts stores, and you can get 130W versions from J. C. Whitney. 

 

ALTERNATIVE CONTROL SCHEMES -- FOG LIGHTS:  To see in fog, it is essential that the fog lights be the only 
lights on; main or low beams just cause glare.  The simplest modification for US-spec cars would be to disconnect the 
RU wire from the inhibit relay, which causes the fog lights only to operate on the top position of the headlight switch.  
Once that change has been made, it would be just as well to remove the inhibit relay entirely as it serves no function. 

A more elaborate idea for convenient fog light operation is to rewire the car so that you can put the headlight switch in 
one position and use the stalk switch to flick back and forth between low beams with fog lights and fog lights only.  
That way, when you come out of the fog bank, you can just flick the stalk to bring on the low beams for better visibility 
in clear air, and just as easily turn them back off when you encounter the next patch of fog.  There’s really no need to be 
able to get to high beams without putting the master lighting switch in another position, since whenever there’s fog 
around you won’t be driving fast enough to need high beams. 

Note that you might need to check local laws here.  At one time it was illegal in some states to drive at night with fog 
lights only, fog or not.  Hopefully, more rational legislators have repealed such laws... what am I saying?  There’s no 
such thing as rational legislators, or the stupid laws wouldn’t have been written in the first place!  Maybe you can get 
by with a set of pilot lights; maybe the cops are stupid enough to think the headlights are “on” -- at least long enough 
for you to get past. 

 

FOG LIGHT AIMING:    Since you aren’t that concerned with distance (you won’t be driving that fast in fog) but you 
are concerned with curbs and the like, you may want to aim your fog lights a bit skewed -- each one aimed a few 
degrees to the side.  Aiming them crosseyed accomplishes the same thing, just using the left light to illuminate the curb 
on the right side of the car.  Whatever you do, though, don’t aim them upward; ideally you want absolutely no light 
above bumper level, even 100 yards out. 

 

DRIVING LIGHTS:  Everyone knows that driving lights are white and fog lights are yellow.  Many people know that 
driving lights focus light far ahead while fog lights spread it low around the front of the car.  What many people seem 
not to know is that fog lights are mounted low on the front of the car, as close to the ground as possible, while driving 
lights need to be mounted high.  Above the bumper at least; rallye cars mount them on the roof! 

In other words, the lights mounted under the front bumper on the XJ-S really need to be fog lights.  Fog lights will 
work great here; driving lights won’t. 

 
 

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Of course, the reason you want driving lights is because you hate the looks of the yellow lenses.  If so, here’s a better 
idea:  Install a set of modern fog lights with clear lenses and the dichroic filters right on the bulbs themselves -- which 
appear blue when the lights are off.  These are better than the old yellow fog lights anyway. 

Or perhaps you want driving lights because you can’t see well enough with just the headlights on.  This may be a valid 
reason if you have the US-spec Carello headlights, but with any of the other configurations of headlight on the XJ-S 
you’d be better off upgrading the headlights themselves as described in the earlier sections. 

If you must install driving lights, kits are available everywhere.  Perhaps the best place to mount them on the XJ-S 
would be within the upper grille. 

As always, you get what you pay for; really good driving lights will provide a carefully-controlled pattern of light down 
the road, while cheap ones will just throw light everywhere and cause glare in rain and the like. 

 

DRIVING LIGHT AIMING:  How you aim driving lights will perhaps depend greatly on the light pattern they provide. 
 If they project a tight beam, you’ll probably want to aim them straight down the road to take advantage of that pattern.  
If they just provide a flood of light in the forward direction, though, you might consider aiming them crosseyed or 
skewed so they help illuminate the sides of the road in curves. 

 

ALTERNATIVE CONTROL SCHEMES -- DRIVING LIGHTS:  If the car is fitted with driving lights, it might make 
sense to rewire the XJ-S so that all the headlights and driving lights work at once.  In fact, later US-spec XJ-S’s came 
with a master lighting switch with an additional position that operates all six lights.  It may be possible to retrofit this 
switch into the earlier cars.  Or, you can simply rewire the “inhibit relay” scheme in the earlier cars, allowing high 
beams and driving lights to be used simultaneously; it might also be a good idea to add relays to prevent overloading 
any circuits. 

With the options available for improving the headlights, there really is little reason to operate the driving lights 
simultaneously to get more light; you should be able to get plenty of light from the main beams.  However, the driving 
lights might make excellent “cornering lights” if you aim them towards the sides of the road. 

In many US states, there once were laws that prohibit there being more than four headlights on a car.  Jaguar’s intention 
for the inhibit relay was to prevent use of the high beams while the fog/driving lights are on, thereby making the 4-
headlight US-spec car comply with the law.  It is unknown how these laws have evolved now that the law requiring 
standardized headlights has finally been eliminated (thank God!).  The owner is advised to check his state’s current 
regulations before rewiring for all six lights to operate at once. 

If your desired wiring scheme requires another switch, John Goodman points out that the UK cars have a different 
headlight switch which can be pushed in to turn on “fog lights” at the rear of the car; this push facility could be used for 
whatever your little heart desires, leaving your dash uncluttered with additional switches. 

 

 

Horn

 

 

Steve S had his horns quit working, and found that the problem was a lack of ground connection at the steering column. 
 There is a little copper spring that rides on the rotating shaft in the center of the column to electrically connect it with 
the outer casing -- but the outer casing may not be securely grounded!  “I've run a separate earth from outer column to 
car body and everything’s OK again. 

“I couldn't find any proper earth wire from outer column to body; looked like Jag relies on the four bolts which hold the 
column to the body.  I gave these 4 bolts an extra tweak but it didn't make any difference.  I ran a 3" long wire from a 

 
 

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convenient bolt head (looked about m4) on the plate on the front of the steering column lock mounting plate to a cluster 
of 4 black wires joining together at a 4 way bullet connector coming from the column stalk switch area.” 

 

 

Radio/Sound System

 

 

INTERCHANGEABILITY:  Greg Meboe says, “During the 70’s and 80’s, the sedans and XJ-S’s used the same radio, 
exactly.  Until 1988 of course, when the radio in the sedan had a curved faceplate to match the new dashboard.” 

 

RADIO WIRING DIAGRAM:  Greg Meboe adds, “On the top of my ’84 cassette player which I removed to install the 
DIN radio, there was printed a nice wiring diagram for the color codes of the Jag radio circuit.  I haven’t been able to 
find this in the general manuals, and it’s valuable information for anyone who is installing an aftermarket radio in their 
Jag.” 

 

RADIO REMOVAL:  Steve Broady, regarding the late-80’s radio:  “Assuming your radio is a Blaupunkt made in 
Korea, you will need to cut a coat hanger into 2 pieces like a pair of U’s to push into the front plate holes to remove 
radio from bracket.  When you pull the radio out of the dash watch for ground strap on left side as bolt protrudes into 
bracket.”  Note that what Broady describes is actually a fairly common type of mounting, and the little U-shaped pokers 
are actually available separately at auto audio stores. 

 

RADIO SECURITY -- REMOVABLE FACEPLATES:  According to Greg Meboe:  “The 86 Jags came with the 
removable-face tape deck, a design which has made radio repair/replacement outfits a lot of money due to its low 
service life.  The face comes off to ward against theft, but the connectors for the face don’t seem to cut the mustard.” 

Vince Chrzanowski, who repairs and restores old car radios, says, “The faceplates can’t be repaired by ordinary 
mortals.  The commonest failures are not in the LEDs, but in the surface-mounted integrated circuits which are hidden 
under mounds of epoxy.  Additionally, the slide controls are among the most failure-ridden we’ve ever seen.  But the 
faceplates can be purchased in repaired form.  Our source for rebuilt faceplates is Southern Autotronics in Virginia (1-
800-446-2880, usual disclaimers apply).  The last time I purchased one, the technician indicated that they were in short 
supply.  That was about two years ago. 

“The 9500 series radio was, in my opinion, not nearly as reliable a radio as the so-called lesser 8600 series.  After 
struggling for a few years to keep the 9500 alive in my ’85 XJ-S (faceplate, tape deck and pc board failures), I opted for 
the 8600 and have been perfectly happy ever since.  Actually, the 8600 is much easier to use and much safer to operate 
on the road.” 

 

RADIO SECURITY -- CODES:  Somewhere around 1986, Jaguars came with a radio that had another security feature: 
if the power was disconnected, the radio would never work again unless the correct security code is entered.  
Presumably, people who steal radios won’t steal one they can’t use. 

Of course, you can choose any repair procedure in the manual, and chances are the first step is to disconnect the battery. 
 If you already went through this and your radio is now nonfunctional (or you have stolen such a radio), you apparently 
will need to contact your friendly dealer to obtain the security code.  You may also need to provide a serial number that 
begins with “B” that is on the case of the radio. 

If you would like to avoid the grief, reportedly there is a product on the market that can be plugged into the cigarette 
lighter.  It uses a 9V battery, and will keep a small amount of power on the system while the battery is disconnected.  It 
will supposedly keep the radio operational, stations programmed, etc. 

 
 

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CONDENSATION DEFLECTOR SHIELD:  Apparently, either plugged condensate drains in the A/C system or 
leaking heater cores have a tendency to dump water on the stereo -- and some of those stereos ain’t cheap!  So, 
Technical Service Bulletin #8685 says essentially that a “condensation deflector shield” must be installed on all XJ-S 
vehicles prior to VIN 163790 whenever the mechanic is working in the area.  The part number for the deflector is CBC 
9193, and it appears to be very easy to install, requiring only 0.10 hours. 

 

SPEAKERS:  The ’83 XJ-S comes with a decent sound system, except that it lacks tweeters.  It is highly recommended 
that if your car doesn’t have tweeters, buy some and add them.  You can just add two in the front -- some people feel 
that only bass notes should come from the rear to give the impression that you are “facing the orchestra” -- or you can 
add one at all four corners to provide a complete surround sound.  Just wire them in parallel with the existing speakers.  
If there are any induction coils in the line to the existing speakers (they are sometimes installed in an inline fuse holder), 
wire the tweeters in before these, so the induction coils serve the existing speakers only. 

There are many types of tweeters available.  The best kind are a 1” or smaller dome tweeter; some may have a dome 
made of plastic or even titanium, but either way they provide excellent high frequency sound and excellent dispersion.  
The size refers to the size of the dome itself, but nevertheless the entire thing is pretty small -- and they’re usually fairly 
inexpensive as well.  The sound from tweeters is pretty directional, so some tweeters come with a mount that allows 
you to aim them -- but even if you just mount them flush in the doors, the sound will be vastly improved over no 
tweeters at all.  Be sure to get 4 ohm tweeters; the 8 ohm tweeters are intended for home systems.  Dynamic tweeters 
will usually come supplied with a capacitor; wire the capacitor in series with the tweeter.  This forms a filter that keeps 
the bass notes from being applied to the tweeter, which might burn it up. 

Another good option is to go to Radio Shack and buy piezo tweeters, Cat. No. 40-1383.  The nature of a piezo tweeter 
means that you don’t care about ohmage or filtering, just wire them in.  They’re cheap, sound good, and are almost 
impossible to damage. 

 

MAKING THE AFTERMARKET RADIO FIT:  Greg Meboe provided some guidance on how to get a fancy new 
stereo to fit in my old Jaguar.  “Your car is an '83, so it would have originally been fitted with a two-knob cassette 
player with manual pushbuttons for play, ff, rr, and eject.  This radio was fitted from ’82 to ’84, inclusive.  The metal 
facia panel (fibre-optic panel) which was fitted with this radio has a cutout which resembles a side view of a foot-long 
hot dog stuffed into a normal-size bun.  Starting in model year 1985, Jaguar began to fit the more modern, rectangular 
faced radios which use a large, rectangular facia cutout.  The fibre-optic panel fitted to 1985 and newer sedans and S’s 
will therefore accommodate any modern DIN radio without modification.  The radio mounting scheme for the Jaguar 
was the same throughout the years, so a person could install a 1985-on Jaguar radio in their pre-’85 car just by fitting 
the later style fibre optic panel.”  This panel is shown on the “Heating and Air Conditioning-Controls” page of the Parts 
Catalogue (besides framing the radio, the panel also holds the knobs for the A/C system).  The part number of the 1986-
on panel is DAC3418. 

“For the structural mounting of the radio, modern aftermarket units seem to have a series of standard 8mm mounting 
holes on the side.  I made up a set of steel brackets to fit these standard holes, and mount the radio in the fashion that 
Jaguar intended -- with the nylon push fasteners in the front.” 

 

BLOWING FUSES:  Typically, the first time you crank up the volume on your high-powered aftermarket stereo 
system, it’ll go silent on you.  Sean Straw says, “There are three fuses associated with your stereo - the fuse in the 
passenger side fusebox (RADIO/CIG LIGHTER), the fuse on the stereo itself (well, any self-respecting stereo will 
have one), and one on the line between the two, which as the manual describes, should be in the console (actually, the 
Jaguar service manuals claim it is "behind the stereo"). 

“I'd installed a new stereo, and I had it turned up a bit, then switched to the cassette, and it just blinked out.  After some 
probing around, I determined that it was the fuse between the stereo and fusebox, and located it roughly forward of the