Gimme a brake
I have a '97 328i that is doing some strange stuff on the brake circuit. I was getting an intermittent "Brake Circuit Failure" message once every few days but it never amounted to much; just shut it off and turn back on, and away it went. I replaced my 4-wire brake switch and thought that would be the end of it.
Well it showed up again sporadically. Then one day it came on again and I thought nothing of it as usual. I happened to have my cruise control engaged around 50mph and approached a red light. Well surprise surprise, the cruise didn't disengage when I pressed the brakes! Took me a second to comprehend what was happening; not a nice sensation.
In any case, the "Brake Circuit Failure" message now comes on every time I use the brake after start-up, and the cruise will never disengage (unless I manually turn it off). Further, ALL brake lights are now non-functional!
The fuse is good, and I have power at both circuits of the brake switch (4-wire switch). The switch is new and appears to be working fine; a multimeter shows continuity on both circuits when the pedal is pressed, as expected. The connector contacts look fine but I cleaned them just in case.
The switch or connector would seem to be the culprit, but both appear fine. Ideas anyone??? I see an X181 connection point in the wiring diagram that I'm wondering about, but this just doesn't feel right.