console error message

000is · 10-07-2008, 11:01 AM

hope someone can help...

my '94 325is keeps getting a 'BRAKE CIRCUIT FAILURE' 'SEE MANUAL'
message on the lcd screen.

all brake lights are working properly...and all fuses are intact.

(I think) it usually occurs when I apply the brakes after putting the car into reverse?

TIA!

_S

forgedcbuser at gmail dot com

Manolito · 10-07-2008, 08:57 PM

Most common problem that generates this message is a failing switch at the brake pedal arm. Get somewhere that you have a wall behind you so you can see your brake lights come on. Press the brakes 10 times or so, fast, slow etc.

If the brake light switch is failing, it may not light all 10 times, when I checked mine, it lit only 7 of 10 times.

If you need a new switch, the switch is inexpensive and not too tough to replace if you don't mind standing on your head. Get a BMW or name brand switch, not a cheap Chinese-made switch, or you may be doing it again in a year or two.

You will bend the bracket when you break the old switch out of it, so make sure you straighten it nice and straight so the new switch centers on the brake arm when you are done.

Jeron · Jeron's Garage

I agree.

I wouldn't bother testing it just replace the switch.

000is · 10-09-2008, 12:38 AM

thanx for the replies guys.

i'll definitely check to see if the switch is dead...

but...

i also got advice that there are actually 2 switches
...one of which may be faulty which explains why the lights still work while getting the error message.

how to tell which switch is the one that needs replacing?

Jeron · Jeron's Garage

I believe the switch itself has two switches internally for redundancy and therefore safety.

ritjeff · 10-09-2008, 03:36 PM

Yeah, mine does it if I am pressing the brakes while turning on the lights. It alternates between brake light failure and brake circuit failure, but the brake lights work just fine every time. I figured it had something to do with an aging computer on my 93 325i. Beats me, but it works, so I refuse to spend any money to replace anything at this point. Heck, I got rear-ended recently (while sitting still with no brakes on) and it still works fine. Unfortunately, the car is a bit banged up now, but still running strong. Gotta love that Bavarian engineering.

Jeron · Jeron's Garage

Brake light failure is usually a cracked or broken filament or a loose connection in the bulb housing. This usually means only one bulb is effected, at first anyway.

I would not ignore the brake circuit failure though. Usually it means that your brake lights are not coming on 100% of the time and it only takes one time to cause an accident.

000is · 10-13-2008, 10:09 AM

thanx all for the opinions/advice...

haven't changed out my switch yet but still infrequently getting the message...
also a new msg that reads '1 BRAKE LITE FAILURE' even though it seems all 3 are still working.

Manolito · 10-13-2008, 01:09 PM

Brake light failure message when all lights are illuminating indicates a current flow imbalance that is enough to set off the bulb out sensor.

It takes surprisingly little imbalance to trigger that sensor.

The bulbs that came from Germany, which you can get from the dealer, are just a watt or two smaller than the bulbs that you buy down at the auto parts store for this car. That can be enough to set off the bulb out sensor.

All bulbs should have nickel (not copper) bases.
All bulbs on a circuit should be identical. It doesn't matter if they are all Europe wattage or all US wattage, but they should all be the same.

Examine the trace around the sockets to see if there is any corrosion or burning that could increase the resistance to current flow to that bulb. Burned traces can be cleaned, soldered, and polished flat if you have a soldering iron and a dremel tool.