E34 5-series Instrument Cluster

[chi1234]

My temperature gauge shoots up to maximum (red), all the way, the moment you switch on the ignition key. This started after, i replaced the engine top, i have also replaced the sensor. I have attached picture of rear of cluster.

[shogun]

That's the low version cluster (02/1988 - 08/1990 - 520i, 524td - Maker: Motometer).
That has 2 rechargeable batteries inside for service intervals. Akku VARTA 500 RST 048 can be replaced by NiCd AA 1.2V approx. 700mAH http://www.netforce-player.de/pet-ra...AGEN/KI/KI.htm

It could be that the batteries ran out and damaged the circuit board. You have to disassemble it and check, shown here
http://www.netforce-player.de/pet-ra.../KI/KI_REP.htm

Disconnect the car battery before you start removing the cluster or removing the steering wheel, otherwise your airbag light will come on.

But as it started after you reoplaced the engine top, it could also be that you installed the wrong temperature sensor! The temperature sensors for the cluster and the DME are different! What is your car VIN? What part number did you install for the sensor? What built yar is the car? Which country version? Which engine?
518i M40
520i M20
520i M50
524td M21
525i M20
525i M50
530i M30
535i M30
M5 3.6 S38


Check here for the sensor with your VIN http://bmwfans.info/

It is always important that we know the model, engine, built month and year, automatic transmission or manual gear, country version, otherwise it is difficult to give a detailed reply.

[chi1234]

It is manual transmission, 520i,M50, VIN: OBL57377, 1993, right hand drive. We tried different sensors but it did not help. Will tis help for more detailed reply.?

[shogun]

With the VIN I found the car was assembled/produced in South Africa, that makes it more difficult, as even the VIN decoder has not much details:

VIN ZBAHB58010BL57377
Type code HB58
Type 520I (ZAF)
E series E34 ()
Series 5
Type LIM
Steering RL / right hand drive
Doors 4
Engine M50
Displacement 2.00
Power 110
Drive HECK / rear
Transmission MECH / manual
Colour ( *)
Upholstery ( *)
Prod.date 1993-07-20


I would disassemble the cluster as per the link above and see if there is some damage on the electronic board. The standard cluster has some problems with old capacitors and people replace the capacitors like shown here
http://bmwe32.masscom.net/johan/dash...dash_caps.html

On my website http://twrite.org/shogunnew/topmenu.html under fixes>>instruments see also the write up about "Replace blown resistor in speedometer"

[chi1234]

Thank you, when i opened the instrument cluster, i found a diode burnt beyond recognition. I do not have the details of the replacement (see attached pic - not mine but a similar unit). It is the diode on the top left side next to the white connector block.

[shogun]

I do not know this cluster very well, have only E32 cluster hi version on stock. Maybe someone with an E34 with same cluster can help you? Which country do you live? Maybe you buy a used spare cluster and replace the board. Or someone on the forum here has one spare for sale.

[chi1234]

I do not know this cluster very well, have only E32 cluster hi version on stock. Maybe someone with an E34 with same cluster can help you? Which country do you live? Maybe you buy a used spare cluster and replace the board. Or someone on the forum here has one spare for sale.

I live in South Africa, i have been looking for a used cluster but can only find the ones with four connectors at the back. I have gone over 45 used clusters and have not yet seen another one with only 2 connectors at the back.

[shogun]

Check German Ebay, look for: BMW E34 Kombiinstrument
for example this one from abenson_E32 ? Check if that fits your car. Trusted seller, I know him personally he ships worldwide
BMW E34 Tacho Cockpit Kombiinstrument mechanisch = mechanical 1389490 8351992
http://www.ebay.de/itm/BMW-E34-Tacho...item339567e87a
more here http://www.ebay.de/sch/i.html?_odkw=...&_sacat=131090
I am also in contact with the owner of the website in my post #2 in Germany, he is an expert on clusters, he will have a look at it and if he has any info for you, I will let you know.

Edit:
got following info from Germany:
According to his files it should be a 1N 4004 Diode - the same type (2 x) are also used above the coding plug between the coding plug and the batteries/capacitors. He will try to find a board and make a photo and will include it in his website, so check some days later there.

[chi1234]

Check German Ebay, look for: BMW E34 Kombiinstrument
for example this one from abenson_E32 ? Check if that fits your car. Trusted seller, I know him personally he ships worldwide
BMW E34 Tacho Cockpit Kombiinstrument mechanisch = mechanical 1389490 8351992
http://www.ebay.de/itm/BMW-E34-Tacho...item339567e87a
more here http://www.ebay.de/sch/i.html?_odkw=...&_sacat=131090
I am also in contact with the owner of the website in my post #2 in Germany, he is an expert on clusters, he will have a look at it and if he has any info for you, I will let you know.

Edit:
got following info from Germany:
According to his files it should be a 1N 4004 Diode - the same type (2 x) are also used above the coding plug between the coding plug and the batteries/capacitors. He will try to find a board and make a photo and will include it in his website, so check some days later there.

Thank you very much. I replaced the batteries, diode and everything else is now working except for the temperature gauge its still shooting all the way up.

[632 Regal]

Thank you very much. I replaced the batteries, diode and everything else is now working except for the temperature gauge its still shooting all the way up.

I would bet that the sensor wire is shorted or grounding somewhere since it happened after working the top end. The burnt diode would most likely indicate the wire grounding.

Have you tried disconnecting the sensor wire to see if it still goes max red?