I am sure this topic (or related topics) was covered here in the past. I even found one recent thread, but it was still not enough to get me up to speed on XJS headlights.

I am trying to sort out a situation with my headlights because they don't appear to operate as I think they should. However, the problem is I don't know what the proper operation of XJS headlights should be!

I grew up with US lingo on headlights: I understand low beam and high beam. It seems that Europeans sometimes (oftentimes?) use main beam and dipped beam instead. I assume dipped beam is the same as low beam and main beam is the high beam, correct?

Now, which one is which in XJS with quad (2x2) headlights? Are outer (closest to the fender) are dipped/low beams while inner headlights are main/high beams?

My local AutoZone shop lists two Sylvania-made headlights for XJS: H5006 and H5001. I assume H5006 should be dipped/low beams that should go fitted as outer lights? And H5001 should be the main/high beams to be fitted as inner lights? Is that correct?

 

Correct


The inboard lamps are the 'high beam'.

Outboard lamps are 'low beam'....although they have two filaments, high and low

Correct

The outboard lamps have two filaments. The inboard lamps are single filament.

In 'low beam' mode, only the 'low' filaments of the outboard lamps are used.

In 'high beam' mode three things happen: 1) the inner high beam lamps come on 2) the 'low' filament of the outboard lamps is extinguished 3) the 'high' filament of the outboard lamps come on

Cheers
DD

 

I think that your car originally came with what are called sealed beam headlights. H5006, H5001. These do not contain bulbs , the whole light is the bulb and must be replaced. A far better option is to replace these with the H4, H1 type. They give a much better light.
In rest of the world speak, you need to look for a set of 5 3/4" headlights that have 2 outer lights that take an H4 bulb (main/high and dipped/low )and 2 inner that take an H1 (main/high ) bulb. The outer can be had with whats called a side, park or pilot light. This is a small 5w bulb. Not needed on your Jag as the front indictors contain a double filament for that .

https://www.sngbarratt.com/us/#!/Eng...5-6d2fac1ab650

https://www.sngbarratt.com/us/#!/Eng...b-3aa788401e6b

https://www.sngbarratt.com/us/#!/Eng...5-7778d8a493ed

 

And the H4 and H1 bulbs are not all created equal. Philips nightbreaker bulbs are MILES better than most.

 

Perfect! Thank you, Doug. Will use this as the benchmark.

I clearly have a problem. In the 'high beam' mode, I have 3 out of 4 headlights coming on. Both outer ones are on, but only one inner one (high beam) is on. Now I understand that all four lights should be on in the high beam mode. I guess I need to get one high beam replacement lamp (H5001).

In 'low beam' mode, I have only one out of two lights working. The one that does not work in the low beam mode, is actually being turned on when I switch to high beam. (This piece is the one that confused me initially.) So, I guess this means that the 'low beam' filament went south in this one, but high beam filament is still ok. But since these are sealed units, this means I also need to get one 'low beam' lamp (H5006).

Will start with those two and see if I can make it shine as designed again

Happy New Year!

 

Do some bulb swapping first to make sure you don't have a wire or contact issue with your bulb connectors or something else. As long as you will expect to change the bulbs you mentioned, you might as well confirm with bulb swapping while you're at it. Put the good outer low beam in placeof the left side and see if it works as it should. Same for the inner high beam one. No need to screw it in place, just plug it in and try it.