LCD Odometer Display Replacement

[supertack]

I know there's a number of e36 owners with the irritating pixel failure on the odometer display of their cluster. I'm not talking about a burnt out bulb here. It's the case where the odometer is fully lit, but the bottom half of the numbers drops off intermittently. It's a defect with the LCD display, but to this point I haven’t found a write up on a particular fix.

I've tinkered with the idea of a new cluster, but there is the issue of getting the new one to match the correct miles & not display the manipulation dot on the gauge. For those not aware, clusters sometime during 1996 went to a coding plug for miles, as opposed to the miles being hard coded into the cluster electronics. If you have a cluster without a coding plug, & want to swap out to a new/used cluster, you need the stealership to code the cluster for you with the proper miles. For those clusters with a coding plug, you can remove the plug on your cluster (with your actual vehicles miles), & put it in the new/used cluster, & the miles from your plug will transfer over to the new/used cluster. The stick in the mud is this, once you do this, a red dot will illuminate at the bottom of the gauge, indicating the miles have been manipulated. To remove the manipulation dot, you need to take 2 steps. First you need to make sure your new/used cluster that you are putting your old coding plug into, has less miles than your coding plug. The electronics are set up so you can reprogram the cluster to accept a coding plug with higher miles, but now lower. Second once you put your old coding plug into the new/used cluster, you need to reprogram it to remove the manipulation dot. The reprogram is done through the clusters diagnostics mode. This mode is accessed by holding the trip reset button down, then turning the key to the first position. You then need to cycle through the diagnostic tests, until you get to test #9-Distance Reading. Once there, holding the reset button for 4 seconds will overwrite the lower miles on the cluster to the higher miles on your coding plug.

Seem like a lot of work to fix a couple odometer pixels? Ya, to me too. So I started thinking about finding a donor cluster (one with maybe a broken tach or speedo that someone wants to unload for next to nothing), & seeing if I can pull the LCD display unit from the donor cluster, & put it into my cluster. Well I've found my donor, but I don't have much of an electronics background.

Does anyone have a thought on how to remove that display from the board of the donor, & retro fit it to my cluster? There is also four clips that hold the display face to the housing of the display unit. On my cluster those clips don't hold the face tight to the housing. I'm wondering if this is the cause of the intermittently bad display, & if simply replacing that face with the donor display face could fix the issue.

Anybody have any thoughts? I'm really just brainstorming, cause trust me, there isn't anything on the web about such a repair. It'd be kinda cool if this boards members could pioneer an irritation shared by a vast amount of e36 & e46 owners alike.

[Jeron]

These are for different models but it might be worth a try.

http://www.x5world.com/articles/x3/electronics-x3/9669-pixel-fix-bmw-cluster-problem.html

http://www.cardomain.com/ride/240317/6

[supertack]

Yah, I've gotta pull the cluster to replace my gas gauge bulb anyway, so I'll take some pics of the display face & housing while I'm at it.

That second write up is for a '96 740il, so I wouldn't think it'd be too different; however, I can take the entire display face off the housing via the 4 clips, where as the write up on the 7 only showed being able to loosen 2 clips enough to spray the cleaner in there.

I'll give that a try.

[Wayne 962]

Probably just need to unsolder the display unit and resolder it on the new one. Easier said than done, if you're not an expert solderer, and if you don't have a good iron...

-Wayne