Brake light out, dashboard "clicking"

[Milan]

Hello!

My offside brake light was out, so, this morning, I tried changing the bulb with a spare I had lying around (which may or may not work!). Now, whenever I depress the brake pedal, I hear a pronounced "click" from behind the dash, and I still see the brake warning light (I don't know if the replacement bulb works, couldn't see behind the car!).

Any idea what might be causing this clicking sound? Maybe a blown fuse?

Cheers,

Milan.

[Milan]

After further investigation, it seems the "click" only happens if the automatic transmission is set to P.

[almcl]

Way beyond my knowledge level here, but does your car have the interlock that prevents gear selection unless the footbrake is applied?

If yes, then you may be hearing the solenoid disengage. Alternatively, I can't remember the location of the bulb failure module, but this may be responsible for the click.

[Milan]

does your car have the interlock that prevents gear selection unless the footbrake is applied?

If yes, then you may be hearing the solenoid disengage.

Thanks for the reply. Yes, I do need to press the footbrake before selecting a gear, but it's never made a loud "click" before today. Not sure why it has suddenly chosen to do so!

I tried changing the bulb, but something is clearly up as I now have no brake lights at all! Can anyone point me towards where the fuse will be on a '94 4.0l?

[Milan]

Oh, forgot to mention, the warning on the dash has now gone, for what it's worth! Quite worrying that I can have no brake lights at all and the the instrument panel bulb isn't letting me know...

[Dimdip]

Just a pointer on this that you may or may not have noticed;
On my early facelift, if the handbrake is on the brake warning light will come on when you press the brake pedal, but not with the hand brake off. It doesn't seem to matter if the gear selector is in P/N/D etc, just if the handbrake is on.

Keeps catching me out now and again (don't use the handbrake that much!)

[almcl]

Now back home and able to check the books. The stop light relay and bulb fail unit are both in the boot, so it isn't them.

The bulb fail unit works by detecting different current flows in the pair of lines to the bulbs so if both go at once you may not get a warning. This is also why, if you put different manufacturer's bulbs in, you may get a warning even when both bulbs are working: they can draw sufficiently dissimilar currents to activate the failure unit. Spring for a new pair of 21 watters in Halfrauds, they're not that expensive.

The stop lights are fed by fuse 19 on the right fuse panel (the underscuttle panel should have a label describing the fuses, if it says something different, go with what it says - Jag documentation is notoriously unreliable in this respect)

While you have the underscuttle panels hinged down to check the fuses, see if you can work out which component is clicking? There are fifteen relays or similar devices on the two fuse panels alone, so you'll be spoilt for choice.

[Milan]

Thanks very much for your help! Fuse 19 was indeed the culprit.

As much as I love my XJS, it's my daily driver and it feels like there's always something going awry with it!

[franrca]

Hi Milan

Was the clicking coming from below your gearstick and did changing the fuse resolve this? I have the same loud click when I put my foot on the brake when in park, but I thought something physically within the gear mechanism had gone awry.

[Milan]

Was the clicking coming from below your gearstick and did changing the fuse resolve this?

It seems to have improved it. As the poster above said:

"If yes, then you may be hearing the solenoid disengage."

I still hear the click, but it is no longer an alarmingly loud noise!