Hi all,

Appreciate any advice on the following: Dipped/low beam headlights abruptly stopped working, both sides.

High beams, park lights, and fog lights all work just fine. - problem is only with the "low beam" headlights.

She is a Canadian 2004 X-Type, so has DRL's.

Checked all fuses, relays, and the bulbs themselves just in case murphy decided to strike both at once - all are good.

Any suggestions as to what to check next? Could it be in the headlight switch? or the DRL circuit somewhere?

Thankyou kindly,

Julz.

 

Julz, it may be possible that you simply have a bad relay. I would say to reverse your high beam and low beam relays first to see if that will fix your problem.

If this does not fix things, I can help you out here. First things first though, what year/month was your car made (written in the driver's door jam). Your year car has 2 different wiring harnesses and they also changed the fuse box numbering. So, I want to make sure I give you good info and not send you on a wild goose chase.

 

Thanks Thermo, again.

I'm unable to swap high beam (R1) and low beam (R11) as they are different sizes.
R1 looks like a 20amp/5-pin relay, and is about half the physical size of R11 (40amp/4-pins) (photo attached).

I benchtested R11 to be sure, it tests fine, have 100ohms resistance through the coil, and upon activation the switched side goes from open circuit to 0.6ohms.

(I'm assuming I have the correct electrical document. I removed R1 to be sure it is the high beam relay, it is.)

Manufacture date is: 09/2004.

Appreciate any pointers, merci beaucoup!

Julz.

High beam (R1) and low beam (R11) 2004 x-type, canada

 

Julz, there are a few other checks that we can do. If you look on the bottom of relay R11, next to the pins, you should see a set of numbers (1 thru 5). Relate these numbers to the openings in the fuse box . NOw, what I want you to do is to get a short piece of solid core wire (say 18 gauge) and cut it about 5-6 inches (12-15 cm) long and then strip the last 1/2" (12mm) off of the wire on both ends. Now, locate the opens for pins 3 and 5. Install the wire between these two openings. Did your low beams come on? If yes, then we know that your headlight circuit is good. If only one came on, then you will need to check fuses F29 and F30 for a bad fuse. If both of those are good, then we have a ballast issue and that will explain why one of your headlights did not work. If both lights did not light, then I would check that you have 12 VDC at pin 3 by connecting a multimeter between pin 3 and chassis ground. If you don't have power there, then you have a problem with your fuse box.

Assuming that both lights lit in the above check, next, install the multimeter (measuring resistance) between pin 2 and chassis ground. With the multimeter connected, turn the headlight switch to the "dip/low beam" position (2 clicks in the clockwise direction). Did the multimeter jump from a very high resistance to essentially a short (under 5 ohms)? If yes, then your ground side of your coil for the relay is working. If no, then you have a problem with either your headlight switch or the interconnecting wiring. Write me and we can work this out.

If your check between pin 2 and chassis was good, disconnect the multimeter, set it to measure voltage and connect it between pin 1 and chassis ground. With the ignition key in the OFF position, you should see 0 VDC and when you turn the key to the RUN position, it should jump to 12 VDC. If it does this, then your problem is the relay. If no, your problem is internal to the fuse box.

This should get you down to a bad part.

 

Years ago I had the same fault on a car (X400) when I worked at the Jaguar dealer. Both dip beams were inop. Normally when one is inop you look at the bulb. Both must mean a circuit fault.
I looked at fuses, relays, harness wires etc.
I finally removed BOTH bulbs and the filaments were.......................BROKEN!!!!!!!!!!!!!!!!! !!!!!!!!!!!

Stupid me did not look to the obvious.

Did you test the bulbs or light them with 12V?? They can look good but??????

I replaced BOTH bulbs and sent the car on it's way!!!!!!!!!!!!!!!!!!!!!!!

bob

 

Hi Thermo & Bob,

Thanks for the excellent advise and detailed steps, just finished, in the pleasant evening snow...

1- I jumpered the relay connections as advised - no change
2- I checked - had 12v at the relay, (I'm unsure of the correct nomenclature, but had 12v both on "switch" and "output" paths, as expected)
3- As the relay was passing 12v correctly, I checked at the headlight - a 12v differential was present, no light.
4- I turn off the engine, and see I have continuity/almost zero resistance between the bulb terminals (as per an intact bulb)
5- I remove the bulb, bad bulb(s)! The filament looks almost melted inside on one lead.

6- At this point I realise my error. Earlier, when testing the bulbs, with all switches off, I just connected the multimeter to the terminals of the bulb - expecting to see continuity/low resistance with a good bulb, and open circuit with a bad bulb.
I saw continuity/low resistance. I did not remove the terminals - I tested with the terminals intact, not thinking there could be another path between them.
It turns out that, when the car is switched off, both leads of the headlight get connected to ground(?) - I had assumed one lead would be to ground, and the other +ve lead would be floating/disconnected when switched off, and +12v when the relay is on.
This was my error the +ve lead, is connected to ground when switch off, there is continuity between the two leads, near zero resistance, same as a light bulb, when the light is turned off.

My Lesson: remove at least one lead from the bulb before testing bulb status

So, my problem, like Bob's, was both bulbs had somehow gone at the same time. Don't generally believe in concindence - I wonder if this could be a symptom of some other issue?

Thermo: Thankyou for all the guiadance and steps, I now have a much improved understanding of how to troubleshoot similar problems in the future.

I'd like to offer a thankyou: I work in industrial 3D printing & scanning, using a range of plastic materials, including ABS and Ultem.
https://www.curbellplastics.com/Rese...aterials/Ultem

If you have trouble sourcing a particular piece for your vehicle, and you can send me an identical piece, or the broken piece glued - I can 3d scan it, print a duplicate, and return them to you. (gratis). No problem to create mirror images of parts, for example perhaps you have the left-hand version of something, and need the matching right-hand version...

And/or if someone needs a hard-to-find piece from a 2004 X-type, I can scan the matching part from my vehicle, print a duplicate and send to you.

I do not have a metal printer yet, so only plastic parts for now, but ABS and Ultem are surprisingly tough...

Cheers Community,

Julz.

 

Julz, thanks for the offer. I will have to keep you in mind if I get a wild idea in my head (there's lots of ideas floating around). Good to hear that you got it figured out.

 

The reason I did not suspect the bulbs was that "Who would drive with BOTH bulbs out?"
You would assume that when one was inop, you would replace the bulb.
When both are inop, there MUST be an electrical fault..... WRONG!!!!!!!!!!!!!!!!!!

bob