barke wear inicator

Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic

   We have an E30 306i touring (92 vintage) and regardless of having new discs/pads/fluid and sensors recently fitted, in wet weather we get the brake warning light coming on. It stays solid red, and doesn't extinguish. We have checked as much as we can think of, re-installed the sensor/wire/pads etc, but the result is the same?
Anybody have any ideas?
Cheers
AG

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
M3AG Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II 7 series & e36 m3 registrar! (Madness) Joined: 17-October-2002 Location: Good Old Hertfordshire Status: Offline Points: 1644	Topic: barke wear inicator Posted: 18-October-2002 at 14:04
	We have an E30 306i touring (92 vintage) and regardless of having new discs/pads/fluid and sensors recently fitted, in wet weather we get the brake warning light coming on. It stays solid red, and doesn't extinguish. We have checked as much as we can think of, re-installed the sensor/wire/pads etc, but the result is the same? Anybody have any ideas? Cheers AG

Sponsored Links

kbannon Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Admin Group E39 525i Sport Individual Joined: 09-October-2002 Location: 64 Zoo Lane Status: Offline Points: 15508	Posted: 18-October-2002 at 14:14
	I have a similar problem, the source of which I am unsure. However, as I am aware of how much is left on my pads, I don't need it and subsequently when replacing the SI board in the instrument cluster I removed the bulb for the brake light sensor. Killian
	Current: 2009 E60 520d "Sport" tractor Previous: 1989 E30 320i SE 1997 E39 523i 2003 E39 525i Sport Individual

M3AG Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II 7 series & e36 m3 registrar! (Madness) Joined: 17-October-2002 Location: Good Old Hertfordshire Status: Offline Points: 1644	Posted: 18-October-2002 at 16:11
	hat's going to have to be my solution, bulb removal, it's really strange, we've done electrical tests on it, but to no avail! Cheers Killian

pcbim Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Groupie Joined: 12-October-2002 Location: Bristol Status: Offline Points: 80	Posted: 18-October-2002 at 16:43
	Quote: Originally posted by M3AG on 18-October-2002 We have an E30 306i touring (92 vintage) and regardless of having new discs/pads/fluid and sensors recently fitted, in wet weather we get the brake warning light coming on. It stays solid red, and doesn't extinguish. We have checked as much as we can think of, re-installed the sensor/wire/pads etc, but the result is the same? Anybody have any ideas? Cheers AG By reading your post this only occurs in wet weather correct ,, im thinking the rain is somehow getting into the circuit and affecting it somehow , check all the conections under the all wheel arches , and also any damaged cables near that area ,
	2002 320d tourer

kbannon Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Admin Group E39 525i Sport Individual Joined: 09-October-2002 Location: 64 Zoo Lane Status: Offline Points: 15508	Posted: 18-October-2002 at 22:18
	oops - in my rush to read the post quickly (high internet costs in Ireland! ) I didn't read that! Killian
	Current: 2009 E60 520d "Sport" tractor Previous: 1989 E30 320i SE 1997 E39 523i 2003 E39 525i Sport Individual

diaa salah Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 20-October-2002 Location: Egypt Status: Offline Points: 2	Posted: 20-October-2002 at 14:17
	same here, on my 88 E30, even after installling new brake pads, and new sensors, I still get the same red light, and its on my nerves.

M3AG Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II 7 series & e36 m3 registrar! (Madness) Joined: 17-October-2002 Location: Good Old Hertfordshire Status: Offline Points: 1644	Posted: 21-October-2002 at 11:47
	It now does it all the time, so I'll have to resort to removing the bulb, and rely on my inspections of the brakes at service intervals. Cheers guys, nice to see it's a more or less common problem.

Nick Members Profile Send Private Message Find Members Posts Add to Buddy List Bavarian-Board Contributor BMWCC Area Organiser Yorks & Humber Joined: 21-October-2002 Location: God�s own county... Yorkshire Status: Offline Points: 1319	Posted: 21-October-2002 at 20:48
	It's a common fault... if it gets on your nerves, just unhitch and unplug the rubber connection on the front strut....easy... and while you are down there ponder as to why they only put the sensor to one wheel !!

M3AG Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II 7 series & e36 m3 registrar! (Madness) Joined: 17-October-2002 Location: Good Old Hertfordshire Status: Offline Points: 1644	Posted: 22-October-2002 at 09:52
	Nick, Is that under neath the strut (i.e. in the wheel arch) or under the bonnet. I'll look later Cheers AG

kbannon Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Admin Group E39 525i Sport Individual Joined: 09-October-2002 Location: 64 Zoo Lane Status: Offline Points: 15508	Posted: 22-October-2002 at 14:38
	Nick are you sure that unplugging the sensor stops the light coming on? That would just break the circuit - same as if the pads wore down and therefore the light comes on. I believe some cars (USA?) have a sensor on the right rear side. M3AG The sensor plugs into a brake pad on the left front caliper, its wires come through the wheelarch and are clipped onto the shock. The main wire (coming from the ECU/Dash (?)) joins the wires from the pad somewhere near the caliper. If you remove your wheel you should see what we mean.
	Current: 2009 E60 520d "Sport" tractor Previous: 1989 E30 320i SE 1997 E39 523i 2003 E39 525i Sport Individual

Alan Kirkaldy Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 11-October-2002 Location: United Kingdom Status: Offline Points: 15	Posted: 23-October-2002 at 07:52
	I have a similar problem with BRAKE WEAR SENSOR on my 316i, but it seems to come on (and off) with bumps in the road! Opinion points to the TRANSISTOR on the SI board. Apparently a transistor is needed so the electronics can distinguish between the various states of (a) being connected to a pad with material left on it; (b) not being connected (eg wire failure, disconnection etc); (c) being connected to a worn pad (shorting?). In THEORY, a simple electronics job (??) Further, on my 325i, the light doesn't come on when the ignition is switched on (CHECK Mode) but does briefly while cranking the engine, goes out when engine starts.

M3AG Members Profile Send Private Message Find Members Posts Add to Buddy List Really Senior Member II 7 series & e36 m3 registrar! (Madness) Joined: 17-October-2002 Location: Good Old Hertfordshire Status: Offline Points: 1644	Posted: 23-October-2002 at 09:10
	Ours used to come and go when driving over bumps, now illuminates all the time! It only started after we had new pads etc (the dash light telling us they were due) before that it never showed.

Nick Members Profile Send Private Message Find Members Posts Add to Buddy List Bavarian-Board Contributor BMWCC Area Organiser Yorks & Humber Joined: 21-October-2002 Location: God�s own county... Yorkshire Status: Offline Points: 1319	Posted: 23-October-2002 at 18:11
	Alan, we are talking E30 here... 'smart' transistors indeed! The sensor in the pad completes the circuit when it wears down enough to allow the exposed contact to touch the metal brake disc.. thats why it sometimes flashes on over bumps, there is a momentary circuit, usually with old sensors that have crumbled away allowing contact. Moisture can also be an issue, in the sensor itself or in the rubber connector that should be in it's little holder on just above the caliper.. but is usually just dangling loose. The si board has many gremlins of its own, usually warning you of failiures via the check panel lights.... pay no attention to this, it is just a trick! Nick

Alan Kirkaldy Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 11-October-2002 Location: United Kingdom Status: Offline Points: 15	Posted: 24-October-2002 at 07:35
	The transistor was invented in 1947.

Nick Members Profile Send Private Message Find Members Posts Add to Buddy List Bavarian-Board Contributor BMWCC Area Organiser Yorks & Humber Joined: 21-October-2002 Location: God�s own county... Yorkshire Status: Offline Points: 1319	Posted: 24-October-2002 at 19:01
	Quite... but I don't think that any of the E30's have any electrickery that can distinguish the various faults.... it is just a simple circuit. The 'motherboard' behind the dash is a different cookie... if your fault is in there you may be a lot better off with another one from the scrappie... unless of course you know a radio techie who will work on it as a hobby rather than as a labour charged job... ...anyhow, this is only the brake sensor we are talking about... these things are famously unreliable, esp on cars of this vintage.... just like the service lights, do not rely on them... better to look for yourself at the pads, steering on full lock...look down the hole in the back of the caliper and you will see the pads, the friction material should be at least as thick as its backing plate. Nick

m3geezer Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member II Joined: 31-October-2002 Location: United Kingdom Status: Offline Points: 234	Posted: 31-October-2002 at 14:58
	just unplug the connector, this will light the brake pad sensor light, then short the two wires together, if this doesn;t keep the light out then try the rear pad sensor on the oppersite corner. the theory of the brake disc completing the electrical circuit is incorrect as the system requires a complete circuit to put the bulb out! often when the light starts to flicker it is a broken wire in the sensor circuit, often down around the front strut legs.