abs light stays on
Moderator: martauto
I unplugged the relays for my ABS which meant the ABS light was always on. This is an MOT failure so i took my clocks out and chopped the wire for the bulb and soldered two new ones to the oil light. This means it comes on with the first click of ignition and goes out when started. This may not be what you after but is a definate fix!
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beemerbird
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There is a fusible link in the ABS relay which serves the purpose of protecting the ABS electronics from power spikes (jump starting the car) or excessive conditions - I've heard that a the 'baking' process during spray painting can cause this.
The proper solution is to source a new ABS relay.
If, however, you take the relay out (situated in the glove box, towards the upper front) and take it apart you can confirm this from a visual inspection. If at this point you accidentally solder in a very thin piece of wire to replace the burn out link, you will have achieved a BAD BAD bodge, but your unprotected ABS electronics will think the relay is good and turn the light off as requested.
The proper solution is to source a new ABS relay.
If, however, you take the relay out (situated in the glove box, towards the upper front) and take it apart you can confirm this from a visual inspection. If at this point you accidentally solder in a very thin piece of wire to replace the burn out link, you will have achieved a BAD BAD bodge, but your unprotected ABS electronics will think the relay is good and turn the light off as requested.
If it ain't broke, fix it till it is
Interesting thread. Oh for the joys of having a warning light that actually works! Mine doesn't exists and I've an ongoing thread in trying to find the b***dy lampholder!
Needless to say the ABS doesn't work - this relay in the glovebox - would it be silver by any chance and is it a common failure point with ABS? Might be a quick fix for me even if I can find the light to tell me what I already know....
Needless to say the ABS doesn't work - this relay in the glovebox - would it be silver by any chance and is it a common failure point with ABS? Might be a quick fix for me even if I can find the light to tell me what I already know....
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beemerbird
- Married to the E30 Zone

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I believe that the fusible link in the relay is a common failure point in the ABS system, and is designed to be as such - it's a lot cheap replacing a relay than replacing the ABS ECU!
The main identifier in my mind for the relay is that it has an inbuilt metal clip that allows the relay to be clipped to the metalwork in the upper glove box area, towards the front.
Checking this fuse relay won't help you if you have no ABS light, as in failure mode the light is always on.
If you have no ABS light, I would say you either have a duff lamp or no ABS in the first place
The main identifier in my mind for the relay is that it has an inbuilt metal clip that allows the relay to be clipped to the metalwork in the upper glove box area, towards the front.
Checking this fuse relay won't help you if you have no ABS light, as in failure mode the light is always on.
If you have no ABS light, I would say you either have a duff lamp or no ABS in the first place
If it ain't broke, fix it till it is
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beemerbird
- Married to the E30 Zone

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I don't have a picture, but the relay is by itself, very near the front of the opening of the top part of the glove box, clipped on with its integral clip. Fairly obvious if you have a look.
Either silver coloured, or black if my memory serves me right.
You may have to allow the glove box liner to drop down to see it, but I can't actually remember
Either silver coloured, or black if my memory serves me right.
You may have to allow the glove box liner to drop down to see it, but I can't actually remember
If it ain't broke, fix it till it is
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mrLEE30
- E30 Zone Team Member

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also worth checking the condition of the ABS sensor wires, these can be seen by removeing the wheels and you will see the sensors and wires. years of virbrations casue the wires to break and thus the ABS system does not work.
And Jason, i would like to know in what world you consider your option a fix?
And Jason, i would like to know in what world you consider your option a fix?

- Brianmoooore
- E30 Zone Team Member

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- Joined: Mon Jan 10, 2005 11:00 pm
If the light stays on from the point of turning the ignition on, and not just comes on again when you drive away, the problem won't be anything to do with the wheel sensors or their wiring. This is only tested when the wheels turn.
The silver 'relay' can be tested by unplugging it, and linking together the red wire and the red/yellow wire of its socket. The link should be put in place after the engine is started.
If this restores the ABS to working order, then the 'relay' has 'blown'.
I can't fully agree with the advice that the 'relay' can be repaired, because it contains two sacrificial components. One is the fuse, whose demise is obvious, but there is also a zener type diode in there, whose purpose is to blow the fuse, and occasionally lay down its life doing so.
If the diode is blown open circuit, the repaired 'relay' will no longer offer its protection to the ABS ECU from voltage spikes, compromising its 'fail safe' design.
The silver 'relay' can be tested by unplugging it, and linking together the red wire and the red/yellow wire of its socket. The link should be put in place after the engine is started.
If this restores the ABS to working order, then the 'relay' has 'blown'.
I can't fully agree with the advice that the 'relay' can be repaired, because it contains two sacrificial components. One is the fuse, whose demise is obvious, but there is also a zener type diode in there, whose purpose is to blow the fuse, and occasionally lay down its life doing so.
If the diode is blown open circuit, the repaired 'relay' will no longer offer its protection to the ABS ECU from voltage spikes, compromising its 'fail safe' design.


