Another dash light issue

[CaffeinatedSoul]

Ok, I've tried to google this but cant seem to find one that fits my issue exactly. Most people lose ac lights or the OBC is fine.

My cluster and OBC lights stopped working, but just the red back lights on the cluster and OBC. The only things I dont have are the OBC and red cluster backlights lights. I still have lights for windows, ac, climate control, fog lights, hazards, blinkers and defrost. When my head lights are off, the OBC will light up just fine until I turn my head lights on again. I know the lights are good because randomly all the lights will just start working again.

I've swapped the dimmer switch out with another one and it didnt seem to change anything.
Fuses all seem good and put a new one in just in case.
Once in awhile a smack on the dash fixes it, but thats rare.

What am I missing here? Why does it work for awhile then stop working for awhile?

[cirrusblue]

THat sounds very wierd, but electrical issues with headlights engaged can often be a grounding issue... you may want to check the voltage and corrosion on yoru engine grounds.

[CaffeinatedSoul]

I've been chasing an erratic idle miss fire so I've checked all the grounds under the hood that I can find. Is there somewhere else I could look?

[CaffeinatedSoul]

Still fighting this and don't know what else to do outside of spending money I don't have on parts that might not fix it. Why would the obc light work fine, then stop when I turn on my headlights? I swapped a different headlight switch and it has the same problem.

[cirrusblue]

There is a big ground under the car where the engine connects to the frame rail.

I mean, I'm guessing here because it all does sound wierd. The OBC has a constant power, and an illumination power. If you don't get lights when the headlights come on, what does it look like? I'm assuming the obc doesn't turn off.

If your harness has been messed with, or it's got bad grounds then you have to trace it back.

Do you have a voltmeter, make sure you're not running low.

There are better electrical guys than me for sure, but you aren't getting much advice because this and sunroofs are both unpopular subjects.

I'd check your voltage. Grounds, alternator, voltage regulator, etc.

If that's good, then work backwards. Do you have a 6 button or 13 button obc?

[CaffeinatedSoul]

There is a big ground under the car where the engine connects to the frame rail.

I mean, I'm guessing here because it all does sound wierd. The OBC has a constant power, and an illumination power. If you don't get lights when the headlights come on, what does it look like? I'm assuming the obc doesn't turn off.

If your harness has been messed with, or it's got bad grounds then you have to trace it back.

Do you have a voltmeter, make sure you're not running low.

There are better electrical guys than me for sure, but you aren't getting much advice because this and sunroofs are both unpopular subjects.

I'd check your voltage. Grounds, alternator, voltage regulator, etc.

If that's good, then work backwards. Do you have a 6 button or 13 button obc?

When I turn my headlights on the OBC goes from normal brightness to looking like the car is completely off, but I can still change what it shows on screen.
I found out the other day that it has something to do with the dimmer switch, even though I swapped it out and nothing changed. If I smack the plastic below the switch it will all light up. Any specific ground come to mind in that area?

[cirrusblue]

http://www.bimmerforums.com/forum/showthread.php?1925595-E30-Dash-AC-computer-not-illuminating-with-lights-on

Here's a similar post.
But this guy is having issues with all the dash lights.

I'd prob. pull out the radio and see if some wires are cut back there.
The OBC has a separate harness, if that's the only light having an issue - it's prob. gettign under 12v so won't run. It could be loose or cut wire. If it were me, I'd pull the head unit, check the OBC harness, and see if jigging, or using DEOXIT on the connectors will give you more juice. Your banging, may just be jiggling a loose connector. This is what I'd do.

[ColinD]

I just had this exact issue on my 1990 325is. Cluster illumination and OBC would
not light up when turning on the Headlights. I removed the cluster and traced
the "wiring" for the illumination bulbs across the printed circuit board to where the 26 pin connectors come in. Using a multimeter I checked for continuity between the bulb sockets and the appropriate pins where they are soldered to the board. I found one that was intermittent - if I rested the probe on top of the pin there was no continuity; if I pushed it a little sideways there was continuity. Resoldering that pin to the board solved this problem.

I found a helpful electrical diagram here:

http://www.armchair.mb.ca/~dave/BMW/e30/e30_89.pdf

Look at: Light switch details 6300-1 Dash lights
You can see why a power interruption in the cluster lighting circuit can also take out the OBC lighting.

[itsonlygeorge]

Some of the power for the OBC goes through the cluster. I had only half the cluster lights go on and the OBC backlight was always off. I had to replace the cluster main board to fix this issue.


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