Jaguar XJ-S. Manual - part 164

 
 

651

H4 bulbs have a large circular metal base with three alignment tangs, one larger than the other two, and a 3-prong plug 
that will fit the same socket as a US-spec sealed beam -- three large (5/16”) spade terminals arranged as three sides of a 
square.  If your headlights use H4 bulbs, they are readily available -- or you can use HB2 or 9003 bulbs, which are 
exactly the same.  In Europe, these bulbs are called 472.  The French cars use a 476 for the yellow color. 

 

SEALING NON-SEALED H4 HEADLIGHTS:  H4 headlight assemblies are nothing resembling sealed; in fact, the 
back end is open enough you might consider it ventilated.  To prevent moisture getting in and deteriorating the 
reflector, the assemblies include rubber boots that fit over the back end of the headlights.  Note, however, that installing 
this boot will keep the assembly warmer; this doesn’t normally pose a problem, but if you’re using the big-wattage 
bulbs you might consider the tradeoffs between how hot the bulb gets and how big a problem moisture is. 

Other cars, including Hondas, use rubber boots that appear remarkably similar on normal sealed beams.  Perhaps one of 
these boots could be used when the original H4 boots are damaged or missing. 

 

CIBIE REPLACEMENT:  John Goodman reports from the UK: “Jaguar enthusiasts here actually change to the four 
headlamp system because of improved lighting available.”  Goodman isn’t talking about installing the four crummy 
sealed beams used in the US; he’s talking about installing four 5¾” round E-code units with H4 bulbs -- meaning the 
UK car goes from two H4 bulbs to four.  He describes the kit from Jaguar, JLM 10357: “All 4 lights are the same and 
still use the H4 bulbs.  A link wire supplied with the kit only enables the outer lights on dip.  Could easily be wired for 
both pairs on dip, but would screw up the dim/dip and not sure if it’s legal.  Looks like it’s been done this way for 
simplicity of owner installation.  Although it remains a mystery why the genuine Jag kit did not have dedicated driving 
lights for the inner pair with H1 bulbs.” 

“If you have converted to four headlamps, the headlamp washer/wipers are now redundant, but you can utilise the 
additional separate pump for the headlamp washers (modify the wiring) to power one side on your screen washers, 
works well.”  Of course, this only works if you have an ’88-on car with two separate nozzles -- or have added a nozzle 
in addition to the original single one. 

If you convert to four round H4 headlights, you should read the section on that headlight arrangement starting on page 
646. 

 

UK DAYTIME RUNNING LIGHTS:  There is a circuit in the mid-80’s-on UK cars only that operates the low beams 
at reduced power to provide a running light-type illumination, apparently as a result of some law.  Richard Mansell 
quotes “my owners manual which states: In the UK the headlamps are automatically switched ON in a dimmed dipped 
beam mode when the side lights are switched ON and ignition switch is in position ‘2’.  This prevents the vehicle being 
driven with side and tail lamps only.”  John Goodman says it is “Controlled by a relay thingy by the headlamp fusebox 
(this on UK cars came in around ’86 ’87).” 

Goodman continues:  “It gets all screwed up if you try to install non-standard brighter wattage bulbs.”  Regarding the 
kits available in the U.K. to convert to the US-style four headlight system, he says “When I converted my previous XJ-
S to 4 headlights the dim system still works because all 4 lights are the same and still use the H4 bulbs.  All lights have 
dual filament bulbs, so 4 x 55w on main beam, however only the outer ones are ever wired up for dipped beam (not 
sure if this is a legal reason).” 

If you happen to have such a UK-spec car and don’t want to convert to four headlights, one nice option is the 100/55W 
H4 bulb from Wiko mentioned above.  Since the low beam is still 55W, same as the stock H4’s, the dimmed dip feature 
will still work as intended. 

 

 
 

652

DOT-approved Carello -- US 1992-on 

 

Composite headlights -- as opposed to sealed beams -- were finally legalized in the US in the name of energy 
conservation via improved aerodynamics, but that doesn’t mean European headlights are now legal.  After all, the US 
DOT couldn’t possibly accept headlights that have proven excellent in Europe for decades.  So, the 1992-on US-spec 
XJ-S has a new type of oblong headlights that say DOT on the lens.  Emile A. DesRoches says the lights are made by 
Carello, and have plastic lenses with three little bumps for aiming.  “The Carello light housings appear to be completely 
polycarbonate with reflectors of the same material plated and apparently epoxied to the lens in order to provide a leak 
free seal (no apparent O-ring, but it appears there's a ridge where the parts join).  These things are very strong/resistant 
to scratching, etc.  I've taken several stones without mishap and what appeared to be a nut or bolt at high speed (yes, I 
got to the track late and stupidly neglected to tape the headlights -- this from an SCCA tech inspector, yet).  I expect it 
would be possible to separate the sections with use of the proper solvent.” 

Side note:  per Daniel Stern, “Carello is a trademark of Magneti-Marelli SpA., Italy.”  That’s right, the headlights are 
made by the same company that makes the ignition system!  They have a plant in the UK, which is why the headlights 
are marked “Made in UK”. 

The Carello headlights come with a nifty adjustment scheme: the up/down and left/right adjusters are readily accessible 
from under the hood.  There is no need to pull trim off or try to jam a screwdriver through narrow access slots to aim 
the headlights. 

 

CARELLO BULBS:  The US-spec Carello headlights are fitted with 9004 bulbs.  These bulbs have a large plastic base 
with a fat O-ring and a D-shaped 3-terminal socket, and are 65/45W. 

I will repeat: the US-spec Carello headlights use 9004 bulbs.  I am sure of this.  But if you start checking other sources, 
you’re probably going to develop some doubts.  Gary Penovich says, “Every website that I visited showed the USA 
spec 94MY using an H4/9003 lamp.  The Osram/Sylvania website shows the incorrect fitting for a 94 as 9003.”  Hey, 
don’t believe me -- but at least pop the access cover out of the wheel well and pull a bulb out and look at it before mail-
ordering something you can’t use. 

 

CARELLO UPGRADES:  When Jaguar was finally permitted to quit using those lousy round sealed beams, the 
headlights improved greatly, right?  Daniel Stern says, “This is a tremendous, tremendous retrograde step in headlamp 
performance.  The transverse-filament 9004 performs worse than many of the old sealed beams, even.  The 9004 
system is inherently bad.  Poor luminance from the filaments, huge amounts of "noise" from 2nd-, 3rd- and higher-
order filament reflections off the bulb walls, nearly impossible to control filament placement once the bulbs have been 
cycled on and off a few times, oodles of wasted light with transverse filament especially in rectangular or oblong 
reflectors...this junk was one of Ford's so-called "Better ideas" in 1983. Shame on them.” 

David Buchner describes the Carello headlights that came on his ‘94:  “When you turn them on, you get a vague 
impression of some light.”  Buchner also owns an earlier XJ-S with four round sealed beams, and reports that the 
Carellos are “much worse.”  That’s pretty bad indeed, since the four round sealed beams suck. 

For a wattage boost (illegal on US roads), J. C. Whitney offers 9004 bulbs in 100/55W and 100/80W versions.  Stern:  
“Badly-made 3rd-world overwattage 9004s (all of them...no reputable company makes such a product) have insanely 
high internal pressure and frequently turn into shrapnel grenades (hopefully inside a headlamp so the destruction is only 
to the bulb and headlamp...otherwise grievous injury can occur when flying hot glass hits flesh or eyes).  Vastly 
increased glare for other road users and backdazzle for the driver...thermal damage to plastic headlamp parts...melted 
headlamp connectors (tiny contact pins in 9004 base).  Brighter bulbs in bad headlamps don't make good 
headlamps...just bright bad ones.” 

Note that, as of this writing, this author has received several reports of use of 100W bulbs in Carello headlights and no 
reports of melted parts, but this nevertheless must be considered a try-at-your-own-risk idea.  Unfortunately, Buchner 
tried high-wattage 9004’s and reported that they had very little beneficial effect. 

 
 

653

The most effective method of upgrading the US-spec Carellos would be to replace the units with the E-code Carellos.  
Not legal on US roads, but not likely to attract attention and certainly a great improvement in lighting. 

Trying to retrofit any of the other headlight schemes found on earlier model XJ-S’s is likely to be problematic; Jaguar 
changed the entire body at the same time they introduced the Carellos, and the new body panels may not even provide 
mounting points for other headlight schemes.  Besides, nobody with Carellos really wants to sacrifice that nifty aiming 
scheme. 

Another option, obviously, would be to add driving lights.  In fact, this is arguably the most viable option here.  The 
driving lights should be wired so that you can leave them off and use the dimmer switch to switch from low beam to 
high beam and back, or turn them on and use the dimmer to switch from low beam to high beam plus driving lights.  
Then you can use the dimmer to switch back and forth between low and high beam in traffic situations where a car with 
good headlights would only need low beams, and switch on the driving lights when you’re alone on rural highways and 
really need to see.  And driving lights are perfectly legal. 

 

E-code Carello -- non-US 1991-on 

 

At the same time the US got the DOT-approved Carello headlights, other countries got E-code Carellos.  These can be 
distinguished from the US-spec Carellos by a marking on the lens: “E11” in a circle.  Also, the E-code headlights don’t 
have the three little tits that DOT requires for aiming.  Besides these minor appearance differences, there is a major 
difference: the E-code Carellos use H4 bulbs instead of 9004’s.  Per Daniel Stern:  “9004 headlamps are not permissible 
in most of the world, and E-code headlamps are required in most of the world.” 

If you need better lighting, consider the nonstandard H4’s discussed below. 

 

More Headlight Improvement Ideas 

 

HIGH-WATTAGE H4’S:  Of the five headlight schemes the XJ-S came fitted with, two used H4 bulbs -- and the 
discussions above suggest replacing the other three with systems using H4 bulbs!  H4 systems provide excellent 
lighting -- but there is still room for improvement.  One way to get better visibility yet is more wattage.  J. C. Whitney 
offers H4 bulbs in 100/80W, 130/90W, and 165/100W.  The 165/100W’s are kinda pricey, but the others barely cost 
any more than standard H4’s.  You can even get the 5¾” round E-code assemblies from J. C. Whitney with the 
100/80W or 130/90W’s already installed for only an extra buck or two. 

Also, Vince Chrzanowski reports that he found 100/55W H4’s at his local electronics wholesaler: Eiko Order Code 
01019-BP.  Eiko products are distributed by: 

 Wiko, 

Ltd. 

 

10490 W. 164th Pl. 

 

Orland Park, IL 60462 

And, no, he claims there is no typo, the name of the company is one letter over on the keyboard from the name of the 
product line. 

Daniel Stern advises that “good quality European bulbs cost no more than Chaiwanese stuff from JCW or Wiko, and 
the wattage ratings on European bulbs are actually correct.  The knockoffs are almost always quite a large bit lower 
than stated, never higher.  This is not the case with European-made bulbs.” 

Note that the light output of incandescent light bulbs is not necessarily proportional to wattage; usually the higher 
wattages are more efficient.  Suffice it to say that high-wattage H4 bulbs will definitely do the trick.  On high beam the 
reflection from a brand-new road sign can be a little blinding.  And when you flash at someone to move over, they 
move over! 

 
 

654

Of course, nonstandard H4’s are harder to find when one burns out -- but if you buy a spare or two, they don’t take up 
much space in the trunk or glovebox.  Or, you could just buy a normal 60/55W H4 from a local store to tide you over 
until you can get a new specialty bulb shipped to you. 

 

HIGH WATTAGE HEADLIGHTS -- POWER SUPPLY CONCERNS:  Since watts = amps x volts and automotive 
bulbs are 12 volt, a 100W bulb will draw over 8 amps and a 130W bulb will draw nearly 11 amps.  Four 130W high 
beams will draw over 43 amps, or 29 amps more than the stock sealed beams did.  You might wanna consider the 
capability of your alternator; the later XJ-S was fitted with a 115-amp unit, but the earlier ones had 66-amp or 75-amp 
Lucas units -- and you’ve still got electronic fuel injection, windshield wipers, A/C system fans, etc., etc. to provide 
power for.  Still, this usually doesn’t present a problem, perhaps because you can’t use high beams too much due to 
oncoming traffic, there’s usually no point to using high beams in the rain when the wipers are going, and since it’s cool 
after dark the A/C fans are always on low speed. 

You also need to consider the wiring and fuses.  See the suggestions for installing relays on page 642. 

 

BLUE BULBS:  There are two distinct types of bulbs that can be referred to as “blue bulbs”.  The first one has a 
dichroic filter coating on the bulb that makes it appear gold.  You have to hold the bulb up to the light and look through 
it to see why it’s blue. 

Are these bulbs a good idea?  The answer is a clear and resounding no.  In headlamp design, the bulb and the 
reflector/lens arrangement must be designed to work together, and in the case of halogen headlight arrangements that 
design is based on the bulb being clear and nonreflective.  Introducing a filter coating does more than simply reduce the 
amount of light emitted (it is a filter, remember, its function is to absorb light); it also introduces a reflective surface 
within the system that causes light to scatter off in directions that the headlight designer was trying very hard to 
preclude. 

There’s no shortage of bad things to say about this crap, but the following excerpt from a NHTSA document sums it up 
pretty well:  “These bulbs began to show up on cars and trucks in early 1998, shortly after the introduction of HIDs on 
more expensive cars.  Having noticed this, NHTSA lighting engineers who regularly participate in SAE Lighting 
Committee meetings asked committee members to discuss the science, engineering, optics and other aspects of these 
new bulbs.  Those engineers were mostly ignorant of the existence of those bulbs in the U.S. market.  Upon being 
shown one of the suspect bulbs, all were surprised by the orange metallic interference coating that was present on the 
entire surface of the bulb capsule because they did not believe that it would allow a headlamp to perform properly.  
During that meeting, a test was performed on the bulb in a headlamp, comparing it to the OEM bulb for the headlamp.  
When set up in a photometry laboratory, the colored bulb reduced peak intensity in the seeing light area of the beam by 
two-thirds, markedly increased the glare intensity in the area where preceding and oncoming drivers' eyes are typically 
located, and the total volume of light emitted by the headlamp dropped by almost half.  The beam emitted using the 
colored bulb, shining on a white measuring screen in the lab, showed a psychedelic array of colors, ranging from white 
near the hot spot to reds, greens, golds, blues and magentas, in vast areas of the beam.  It was remarkably different than 
the performance of an OEM bulb.  While the laboratory at which the meetings were held did not test the colored 
bulb/headlamp combination for compliance with FMVSS No. 108, the plot of its intensities showed that it was 
incapable of complying.” 

These things should be banned -- and they are.  Daniel Stern:  “Simply put:  They are illegal in all of the US and all of 
Canada, Australia, Europe, Japan... A halogen or tungsten bulb that emits blue light is deemed a blue light, and is illegal 
on non-emergency vehicles in Europe, the US, and Canada.” 

The package on a set of Crystal Blue 9004’s in a local store says they are DOT approved in small letters on the back of 
the card, but clearly warns on the front that they are for show car use only and that local laws should be checked before 
installing.  The bulbs themselves say nothing at all.  You don’t need to check the local laws; they are illegal on the road 
-- any road.  And while using Euro-spec H4 headlights in the US might not get the cops’ attention, these bulbs are 
obviously and obnoxiously blue.  They also increase glare on other drivers -- including cops -- so harassment from law 
enforcement can be expected to be constant and unceasing.  As it should be.