Exactly what the title says: my stock '04 XJR has neither horn blowing when I try to toot it. The engine compartment F25 fuse is OK, and the steering controls all work correctly. Any guesses what this might be? Thanks...

 

Possibly short to ground...

 

Interested to know how you get on, the horn in my XJR hasn't worked in over a year.... been to busy to have a look at it.

 

abonano, how would I ascertain whether this is the case? Thanks.

 

scooternva - I would download the electrical manual (here on the forum) and check the ground that is related to the horn assembly. I believe there may be a relay for the horn as well in the engine bay fuse box - I would check that out as well.

 

OK, so now I just need to learn how to check a ground. Thanks.

 

I took a look at some videos online and this is something that's beyond my comfort zone, at least while I'm tinkering on my own. The front brake rotors are going to be replaced on Wednesday by Top Line Jaguar in Springfield, VA, so I'm going to have them check to see if there's a short while they've got the car. I'll be sure to post what the eventual result is.

 

The good news: the culprit was not an electrical short.

The bad news: the horns were corroded and need replacement, to the tune of $227 parts & labor.

 

Bit of a random bump. I finally got round to fixing the horn on my XJR, but don't ask me how I did it...

The fuse location changes depending on the model year of your car, there was a descrepancy between JTIS and what was in my owners handbook, and also the 2006MY wiring diagrams. Diesel XJ's also have a different fuse location for the horn. In any case the fuse was OK.

So here's my steps of diagnosis.

Initially I suspected that the switch in the steering wheel itself had a problem, since i had swapped the wheel some time ago. The steering wheel switch was fine. Easy way to check is take the cover off the engine bay fusebox, and press the horn, you can hear the relay in the fusebox clicking.

Next was to remove the bumper and have a look at the wiring.



Unplug the horns, the black wire is the earth, the yellow-black is 12V. Checking the earth continuity from the connector at the horn to the major earth behind the headlight = OK



Next was to check the 12V at the connector, leave the neg of the multimeter at the earth behind the head light, put the positive in the connector (yellow-back wire) and push the horn = continuity



At this point I was convinced that the horns were dead, I used a little 12V power supply directly on the horns, they made a little "clunk" but no toot if you know what I mean. I then realised that the little power supply wouldn't provide enough current to run the horns (they draw a lot).

So I plugged them back into the car, and surprise surprise they are working again...

Who knows...

 

Cambo351,

Thanks for this timely report. About a week ago I realized the horn on our '04 XJR is malfunctioning. Only the "high" note is sounding, and it seems quieter than it should be. I suspect the horn itself is damaged or failing, but your post will help me rule out other possibilities.

P.S. Correcting this malfunction is an important safety issue because driving in Tennessee without being wrecked by distracted, inattentive or oblivious drivers requires the rather frequent use of the horn!
Cheers,

Don

 

have you tried your finger??
you need a new horn as theyre not seperated to the horn assembly. if one note works everything else in the system is functioning EXCEPT the horn note that no longer sounds

 

I'd been using the finger and flashing the high beams for 2 years, it was never as effective as the horn...

And yeah the horns are a pair, but in the JEPC they are also listed as individual spares, not sure about how they connect together because they are hard-wired. And it seems the horns of the X350 are not shared with any other models...

I bought some aftermarket horns from the local Repco and it wasn't until I put 12V on the new ones and got the same "thud" out of them that I realised the original horns might be OK...