abs dash light

#1

the abs on my car has never worked so tonight i yanked the abs relay, pulled the cover off, and found the little fuse link was indeed broken. attached an alligator clip to close the circuit, plugged it in, and now i can hear three faint but distinct clicks from what i believe is the abs pump when i turn on the ignition (previously there were no clicks). so i guess that’s progress.

here’s the rub: my abs dash light has never illuminated, either before or after my little “fix”. according to ranger no bulb = no abs. should i be seeing this light at some point? is there a way to tell if the bulb is burned out or disconnected without pulling the cluster?

#2

not sure that no bulb=no abs. what does the wiring schematic show, is it wired through the bulb? i doubt bmw would have done that. pulling the cluster is pretty easy. I’d do that. i’m betting your PO pulled the bulb.

#3

If the light doesn’t come on briefly when you start the car, replace the light.

I know it’s odd that a dead light would disable a safety system. Maybe the junior varsity were running the design bureau that day.

#4

I can’t say whether the ABS system is disabled from a burned out or missing bulb. But you need the bulb to trouble shoot the ABS system. Assuming a working ABS light bulb:

If the bulb doesn’t light when the ignition is turned on, the fuse in the relay could be bad, there may be no power or no ground to the ABS module, or the module could be bad.

If the bulb lights when the ignition is turned on and remains lit once the engine fires, the ABS module could be bad, or the ABS unit could be bad.

If the bulb lights when the ignition is turned on, goes off once the engine fires, and comes back on before the car is moved, the ABS unit is bad.

If the bulb lights when the ignition is turned on, goes off once the engine fires, and comes back on while the car is in motion one or more of the wheel speed sensors is bad.

There may be more cases, but those are the ones I’ve encountered.

#5

how does one replace the light? do i need to pull the cluster or is there an easier way? my tach is attached to the steering column which makes it kind of a pita.

#6

The cluster will have to come out to change the bulb.

#7

ABS is a crutch.

#8

yup, bad bulb. stole the check engine bulb from the other side of the cluster, now the light stays on with the relay removed and comes on for a second or two with it installed which i believe is proper behavior. haven’t started the motor or driven it yet, gotta do a proper fix of the relay first instead of using an alligator clip. thanks for the help everyone, will update after i fix the relay, gonna solder in an external fuse. maybe i should wire up an inline switch while i’m at it :slight_smile:

#9

seems to work, abs light did not come on while driving which i assume mean the wheel speed sensors are all working. couldn’t get going very fast (50 mph tops) and the 06s were kinda cold but i think i felt it modulate the brakes. is the abs light supposed to come on when the system activates? mine didn’t.

#10

The ABS light does not come on when the system activates. If you could feel a pulsation in the brake pedal you have ABS.

#11

didn’t think so. between the low speed and cold pads i can’t be 100% sure that it’s working but i’m reasonably confident that it is. w00t, bring on the rain :slight_smile:

thanks for the help jim, see you fri. while testing the abs i checked the throttle linkage and discovered it wasn’t opening 100% when the pedal is floored even though the pedal stop is at the lowest position. time to bust out the grinder and unleash the ponies.

#12

That probably means that the throttle rod bushings under the dash have disintegrated and gone missing.

#13

could be but it doesn’t seem sloppy. i think my car was an auto->manual conversion so it’s possible that some creative engineering took place. the pedal travel has always seemed short so it wouldn’t surprise me if the current stop isn’t quite low enough. i only need to grind off a few mm to achieve full travel.

#14

turbo329is wrote:

You can tell who has it in a rain race, though.

There is no provision in the rules for disabling ABS.

You could have a long argument about “how” illegal non-functioning ABS is (compared to donor tubs that somehow got bent in a wreck so the top of the shock towers are closer together :wink: ).

At this point, if a car doesn’t have functioning ABS (hypothetically speaking of course) it is illegal.

#15

Where exactly is the ABS relay and what does it look like? I need to check mine. My ABS dash light stays on all the time.

#16

It’s above the driver’s left knee. Rectangle of shiny steel 1"X1"X1.5". Pop the cover off and look for a 1/2" long wire. That’s the fusible link that gets blown. Some have had success soldering it back together. I wasn’t one of them.

#17

Steve D wrote:

[quote]turbo329is wrote:

You can tell who has it in a rain race, though.

There is no provision in the rules for disabling ABS.

You could have a long argument about “how” illegal non-functioning ABS is (compared to donor tubs that somehow got bent in a wreck so the top of the shock towers are closer together :wink: ).

At this point, if a car doesn’t have functioning ABS (hypothetically speaking of course) it is illegal.[/quote]
The rules explicitly forbid the removal of the ABS system components. But my interpretation is that nothing explicitly or implicitly requires the system to be functional. So I’d argue that a car with a non-functioning ABS is legal.

#18

Ranger wrote:

Be careful here. There are differences in model years. Specifically the '90 models don’t appear to have this relay. I know because we tore my dash apart looking for one.

I can’t recall 100% but I think they incorporated a fuse or something into the ABS ECU to replace.

#19

jlevie wrote:

That’s the argument (rationalization?) I have been using for the past 2 years. Unfortunately, rule 1.3 might be interpreted to mean it has to function (“Other than the modifications specifically allowed in these Rules, every part of the car must remain as it came from the factory.”)

PS - The rules implicitly forbid removal of the ABS. Maybe there was an explicit rule years ago when pre-ABS cars were eligible?

#20

I could have sworn that it said the system could be removed. I guess I imagined it. I really don’t want to buy 4 new sensors. The wires had rotted away so I just took them off. They are probably in my garage somewhere.