Instrument cluster half-lit ......

[Alex Mc]

In my '88 M3..

When i turn on the lights (parking or headlights), the cluster only lights up on the left side (fuel and speedo) while the right side does not. Also, the clock light on the OBC will go dim..
-For what its worth, every once in a while the right side will light up.. at random.

Any ideas?? Very frustrating.

[DEV0 E30]

Have you tried twisting the knob clockwise? Have you tried hitting the cluster? (Mine has a loose wire, goes away after I hit it)

[Alex Mc]

Yes, rapping on the cluster did work for about two weeks, but it no longer fixes the problem. Something is loose, and I imagine someone has had the same issue - perhaps the solders somewhere? Just looking for as much input as possible before i take it apart..

Alex

[Jordan]

Where the bulb to light the right side of the cluster connects to the main board is loose. Very common. 2 5watt wedge bulbs light the cluster, one for each side.

[Alex Mc]

Thanks Jordan, perhaps the OBC light will be cured as well.. i'll try tomorrow.

[jht3]

Re: Instrument cluster half-lit ......

In my '88 M3..

When i turn on the lights (parking or headlights), the cluster only lights up on the left side (fuel and speedo) while the right side does not. Also, the clock light on the OBC will go dim..
-For what its worth, every once in a while the right side will light up.. at random.

Any ideas?? Very frustrating.

yep, same problem here in my 88 m3. right 1/2 and OBC is out 99% of the time. the OBC is tied to the right 1/2 apparently. i've pulled the cluster and swapped bulbs. doesn't fix it. i've been meaning to pull the cluster again, tear it apart and see if there's an internal problem or some way i can fix it

[Alex Mc]

Re: Instrument cluster half-lit ......

yep, same problem here in my 88 m3. right 1/2 and OBC is out 99% of the time. the OBC is tied to the right 1/2 apparently. i've pulled the cluster and swapped bulbs. doesn't fix it. i've been meaning to pull the cluster again, tear it apart and see if there's an internal problem or some way i can fix it

This is what makes me think its a cracked solder on the PC board somewhere..

[e30Matt]

Just a thought, but isn't the OBC light supposed to dim when you turn the headlights on? It does in my '87 325is.

[jht3]

Just a thought, but isn't the OBC light supposed to dim when you turn the headlights on? It does in my '87 325is.

yes, but when the right 1/2 of the cluster doesn't light up the OBC backlight dies

This is what makes me think its a cracked solder on the PC board somewhere..

that's my hunch too. when i get the time i'm going to take a real close look at the board and touch up the solder joints. i've also lost the left blinker indicator in my cluster

[Nathan]

Just check all the bulbs. They do go out. They are really cheap to replace and more likely than not its the bulbs. But if you OBC goes out too then its probably some bad connection somewhere

[reelizmpro]

Re: Instrument cluster half-lit ......

yep, same problem here in my 88 m3. right 1/2 and OBC is out 99% of the time. the OBC is tied to the right 1/2 apparently. i've pulled the cluster and swapped bulbs. doesn't fix it. i've been meaning to pull the cluster again, tear it apart and see if there's an internal problem or some way i can fix it

This is what makes me think its a cracked solder on the PC board somewhere..

Yup or a burned track on the PCB which is also somewhat common. Just look for discoloration and check with multimeter.

[Alex Mc]

Turned out to be a gap somewhere in the circuit, but i was unable to pinpoint its exact location. To fix it, i simply jumped the right side to the left.. no sweat, and a permanent solution.

:D

[f u z z]

happens to mine, i just kit my horn and it goes on.

[jht3]

Turned out to be a gap somewhere in the circuit, but i was unable to pinpoint its exact location. To fix it, i simply jumped the right side to the left.. no sweat, and a permanent solution.

:D

nice fix. this is what i did to my light switch as i didn't have any night illumination due to the dimmer rheostat being blown.

[jht3]

ok, i yanked the instrument cluster and disassembled it on my desk. i started poking around with my multimeter and found what i think are two hairline cracks on the board. if you're staring at the cluster the breaks in identical spots on opposite sides of the board, right by screws hold the cluster together. the affected items are the left turn indicator and right 1/2 lights. see the attached picture, i circles the affected parts in red. the traces for these are the outermost ones on the board.

is there a way to repair this? i don't know anything about fixing traces