Instrument Cluster Bulbs

[FinalD]

I'm looking to replace the bulbs in the IC as half of mine are dead which is obviously not ideal.
I've found the P/N on RealOEM but what I'm interested in is, if possible, can I change the incandescent bulbs for LED bulbs. If I can, does anyone know of where I can get them? I mean as actual straight swap bulbs, not LEDs that require soldering in etc.

If not, where is best to get incandescent bulbs, ebay, BMW rob them from the IC of my donor car?

[SGP]

As far as I know there are no "plug and play" leds for the ic, but good motor factors should carry the incandescents. Don't be tempted to substitute them with higher wattage ones though, they run too hot. I think the small ones are 1.2w and the larger ones are 3.5w I'd be ordering them from BMW.

[mcbonio]

Yeah the brighter ones will melt the plastic lenses and surround plastic.!

[FinalD]

I don't want to go brighter, it's just a case of:




Half the lights are duff. I'll probably just order them from BMW then and change them all. I mean they've lasted 20+ years anyway so it isn't like I need the LEDs for long life, just figured I may as well change to better tech if I could.

It's only the gauge/dial bulbs that have gone, the lights on etc. ones are fine (although I may as well replace all with the IC out).

[Brianmoooore]

There are only two bulbs that illuminate the dials, with plastic light guides distributing the light. These light guides work best with an omnidirectional light source, so an incandescent bulb will perform much better than the directional light from a LED. LEDs will also not be adjustable for brightness with the dimmer control.
The correct bulbs are readily available from a lot more places than BMW.

[mcbonio]

What kind of bulbs are they and where can we get them? Mine are quite dim, even with the dimmer on full. Will new ones liven it up a bit?

[Brianmoooore]

The 1.2W small ones are 286 type, and I think the larger ones are 505.
Old bulbs sometimes develop a black coating on the inside of the glass, restricting their light output. E30 (and other BMW models) tail lights are notorious for this.

[mcbonio]

Are the 505 capless 3w? The only ones I can find are 24v. Is this correct?

[SGP]

Yes they're capless.

[daimlerman]

Last time I required the 1.2w capless bulbs my local BMW stealer quoted £1.20 per bulb.
Local car accessory place quoted £1.10 each or 10 for £2.50.....

[Oseanosea]

I don't want to go brighter, it's just a case of:




Half the lights are duff. I'll probably just order them from BMW then and change them all. I mean they've lasted 20+ years anyway so it isn't like I need the LEDs for long life, just figured I may as well change to better tech if I could.

It's only the gauge/dial bulbs that have gone, the lights on etc. ones are fine (although I may as well replace all with the IC out).

I’ve had this exact problem on my ‘85 318i since I bought it last June! I replaced all of the little lights in the cluster, but no joy. I’ve been searching forum after forum to find a fix. I’m hoping it’s one of the two lights Brian references below. I just joined E30 Zone today! I’m so happy!

[Steve]

Welcome to the Zone Oseanosea, glad we could help already.

Get some photos up of your car in the members E30s section.

[martauto]

Welcome to the zone mate, it only gets better

Mart.

[Shutthatdoor]

The 1.2W small ones are 286 type, and I think the larger ones are 505.
Old bulbs sometimes develop a black coating on the inside of the glass, restricting their light output. E30 (and other BMW models) tail lights are notorious for this.

(I think they are 504 Brian, 12v as opposed to the 505 24v)

[Brianmoooore]

The 1.2W small ones are 286 type, and I think the larger ones are 505.
Old bulbs sometimes develop a black coating on the inside of the glass, restricting their light output. E30 (and other BMW models) tail lights are notorious for this.

(I think they are 504 Brian, 12v as opposed to the 505 24v)

That's a quote from nearly seven years ago!
You're right though, 504 it is. Important that they're 3W, not 5W, since 5W lamps WILL melt the orange plastic domes.

[ChrisHC]

Something comes loose on the speedo side of mine, but a sharp tap with my knuckles restores it!

[Brianmoooore]

Something comes loose on the speedo side of mine, but a sharp tap with my knuckles restores it!

If you mean a problem with the cluster illumination, it's still probably a blown bulb. Low voltage lamps tend to have short, thick filaments, and the two ends of where it has blown can sometimes touch, making the lamp light again. Once current starts to flow, the magnetic field created by the current tends to hold the two ends together until the lamp is switched off, when they spring apart again.

[ChrisHC]

That's interesting, but not quite what happens, after the last time I tapped the speedo, it stayed illuminated for about 2,500 miles!

[Kelson]

I know this is an old thread, but this is the same symptom I have just sorted on my 325. The left half of the instruments were dark, the right lit. Sometimes the left would light and then go out, sometimes it would not come on at all. All bulbs were fine so after much checking I swapped the printed circuit board and the issue went away, retrying the old PCB, issue remained (so it was not a loose connection accidentally fixed by the swap).

So in my case it was definitely the PCB and I very carefully checked it but could not see an issue. A further benefit is that the new PCB also solved the red light on issue (suggesting the pads were worn out, but they were not and all wiring and sensors were fine).

Thought this reply might help someone else in the future.

[BenHar]

I know this is an old thread, but this is the same symptom I have just sorted on my 325. The left half of the instruments were dark, the right lit. Sometimes the left would light and then go out, sometimes it would not come on at all. All bulbs were fine so after much checking I swapped the printed circuit board and the issue went away, retrying the old PCB, issue remained (so it was not a loose connection accidentally fixed by the swap).

So in my case it was definitely the PCB and I very carefully checked it but could not see an issue. A further benefit is that the new PCB also solved the red light on issue (suggesting the pads were worn out, but they were not and all wiring and sensors were fine).

Thought this reply might help someone else in the future.

PCB?

Ben

[Kelson]

Printed Circuit Board

[coopman]

Not sure if I should be posting a link to a "rival" forum, but I've been replacing various bulbs and have found this quite useful:
http://forums.bimmerforums.com/forum/sh ... st26757741

[Brianmoooore]

I know this is an old thread, but this is the same symptom I have just sorted on my 325. The left half of the instruments were dark, the right lit. Sometimes the left would light and then go out, sometimes it would not come on at all. All bulbs were fine so after much checking I swapped the printed circuit board and the issue went away, retrying the old PCB, issue remained (so it was not a loose connection accidentally fixed by the swap).

So in my case it was definitely the PCB and I very carefully checked it but could not see an issue. A further benefit is that the new PCB also solved the red light on issue (suggesting the pads were worn out, but they were not and all wiring and sensors were fine).

Thought this reply might help someone else in the future.

Are you sure you've got that the right way around? The LH panel lamp is almost next to the white plug, where the power for the lamps comes into the cluster, and the copper tracks from the plug to the lamp are quite wide and short, whereas the two copper tracks to the RH lamp are thin, go right around the top edge of the circuit board, and through several wire links on the back side of the board. Plenty of opportunity for corroded or cracked joints to the RH lamp, but next to none for the LH lamp.
The brake warning fault is almost certainly cracked joints associated with a large resistor located near the temp. gauge.

[BenHar]

Printed Circuit Board

I know that.

Which PCB?

Ben

[Brianmoooore]

Printed Circuit Board

I know that.

Which PCB?

Ben

The cluster mother board. Same size and shape as the whole instrument cluster.

[Kelson]

Yes, I do know my left from right, so yes it was the left side of the dash that was not illuminated - i.e the speedo and fuel gauge near the white connector. Sorry for the misunderstanding, Yes the PCB I was referring to was indeed the main mother board into which the instruments fit.

[Brianmoooore]

The 12 volt feed from pin 23 of the white socket goes first to the LH lamp, then onwards from there, via its tortuous path, to the RH lamp, so there can't be any problem with that track. The 'earth' track for the lamps, from pin 24 splits almost at the pin, so that only leaves about two inches of very visible, thick copper track, to the LH lamp, as the possible problem. Did you swap over the lamp holders between the boards? Or swap them left to right?

[Kelson]

Hi Brian. No, did not swap lamp holders, just had a complete 320i cluster spare (kph unit), so pulled the instruments from that and swapped it into the 325i housing with my original dials. All bulbs etc already in the circuit board came with it.. Its a good point regarding the bulbs.

I will try to narrow down the issue on the board now its out as I'd like to find a fix for it. WRT the red light and that resistor. I did attempt to reflow the solder a few times to no effect. The replacement board fixed that as well, but of course this pair of issues my not be related.

[Kelson]

Further info on the left half of the instrument cluster being dark. I have taken these steps to test it using my multimeter set to 200 ohms (NB when just touching the two probes of the multimeter together at this setting I see 0.4ohms as a bench mark number for continuity)

1 Tested for continuity from pin 24 (the actual pin in the white connector) to the top mounting of the illumination bulb in the PCB - tested ok (0.4 ohms)
2 Tested for continuity from pin 23 (the actual pin in the white connector) to the bottom mounting of the illumination bulb on the PCB - tested ok (0.4 ohms)
3 With the bulb holder in place, tested for a resistance across pins 23 and 24 - 5.3 ohms suggesting circuit /bulb is ok
4 Removed the bulb holder and tested for resistance across the connections - 5.3 ohms suggesting bulb/bulb holder is ok
5 Removed the bulb from the holder and tested across its contacts. First test 5.3 ohms, second test, no reading. Several repeated tests, most with no reading, occasionally 5.3 ohms

Conclusion, the PCB was NOT the issue with the illumination of the left dial (as intimated by Brian), the bulb, whilst looking ok and testing ok some of the time, was faulty.

Now to check out that pesky red light. Thanks Brian for pushing me down to a closer inspection - clearly in my case, the fault for the left instrument illumination was the bulb, not the PCB.

[Brianmoooore]

Conclusion, the bulb, whilst looking ok and testing ok some of the time, was faulty.

This is typical of what I wrote further up the page:

If you mean a problem with the cluster illumination, it's still probably a blown bulb. Low voltage lamps tend to have short, thick filaments, and the two ends of where it has blown can sometimes touch, making the lamp light again. Once current starts to flow, the magnetic field created by the current tends to hold the two ends together until the lamp is switched off, when they spring apart again.

The broken ends can also hook together for periods of time.

[Kelson]

Yep, spot on Brian.

Not having as much luck with tracing the brake pad wear sensor light on fault (NB Car has new pads and sensors all round and as mentioned above, light works as expected with different PCB), Done some tests as follows but I must be missing something (given the new circuit board does not exhibit the same issue. (NB Probes connected show 0.4ohms on the 0 - 200 setting)

1 Resistance across the solder (which has been flowed a few times) of the big resistor - 220ohms
2 Resistance across pins 21 and 23 on the back of the circuit board (blue connector) - 220ohms
3 Resistance at the actual pins 21 and 23 in the blue holder - 220 ohms
4 Bulb resistance 12.8 ohms
5 Resistance of first resistor from that links bottom warning light connector around the top of the circuit board 10.4 ohms
6 This resistances is constant at all points up to the 3 pin item where the circuit goes (not sure what that is)?
7 Between the right most pin of the 3 (facing the PCB) and the centre pin I get a resistance of 797 ohms (same for the left most)
8 From the lower part of the bulb holder to the centre pin I get 808 ohms (which seems right for 797 + 10.4 given my meters limitations)
9 Across the next resistor which will run on to pin 26 (white) I get 388 ohms
10 From the lower part of the bulb holder to the of resistor at 9 I get 1308 ohms (I was expecting 1195 - but that could be my lack of understanding as I know very little about electronics).
11 From the lower part of the bulb holder to pin 26 (inside white connector) I have 1308 ohms

Does that mean the lower part of the bulb holder circuit is good?

The upper part of the bulb holder goes to pins 1, 16, and 19 of the yellow connecting block and all have continuity. Not sure where it goes from there, but guessing some of those are linked 'behind the scenes',