Today, My 1993 xj6, 129000mi brake warning light came on, I
was stopped in heavy traffic so had been waiting for a while
with my foot on the brake when the brake light came on, No
loss of braking, no deviance at all, pedal did not sink to
the floor, nothing, Carefully drove home with no loss in
braking power, But each time I did brake the brake light
would flash a bit, on off, on off depending on how hard I
was braking, If I came to a complete stop it came on fully.
When I got home I checked the fluid level, it looked OK,
Maybe down a tiny bit, I topped it up, Didn't need much, 1/4
cup or less, I figured it was down a bit from break wear,
Went out again & exactly the same thing as above, Brake
light on off depending on how I was breaking, Still no loss
in breaking or any change in pedal pressure, Any ideas,
Note- I did New pads, Rotors & rebuilt the calipers about a
month ago & have not had any problems, Any help would be
greatly appreciated.

 

My first best guess would be a pad wear sensor having a moment. The XJ40 was a little odd with these, and they were dropped in the X300 model.

I could not get ours to stay OFF, so bridged the wires at the pads with a loop wire and forgot about it, no more silly messages to compliment the "bulb failure" we got forever on that car. Dont miss that car one bit.

 

An exact thing happened to me on my Jag that turned out to be broken pedal wear sensors .

 

shoeboy:
From what I understand, a momentary flash of the brake light (and perhaps the ABS light?) can be a sign of an accumulator ball failing to keep pressure. Have you heard any more or unusual noises coming from the ball - a kind of chattering noise? These are exactly the symptoms my '91 is having which, alas, must now wait for the spring season to be repaired.
Scott

 

Yep, Soldered & sealed the brake pad sensor wires & No More Brake light !

 

Good news, and cheap also.

ENJOY

 

Good news, good to see it was that cheap and easy

 

Gotta love those type of repairs. Well done.