Removing the airbag and changing the dash bulbs First you disconnect the negative battery cable. This is critical.
Make sure you have the code for the radio before doing this.







2. Wait a few minutes for the airbag to discharge, then remove the 2 philips screws that hold the steering column cover on the bottom.



Make sure you disconnected the battery. Then you remove the bottom cover on the steering column. When that's removed you will see an orange connector. That's the airbag connector.Squeeze the clip ends and separate the connector. Remove the end that goes to the steering wheel from the post its fastened to.


Using a T27 torx socket or driver, then remove the 2 screws on the back of the steering wheel that hold the airbag in place.



Next you carefully lift the airbag assembly off of the wheel and disconnect the plug on the back. It comes straight out to remove. Then set the airbag aside in a place where it won't get disturbed or damaged.


Then you remove the 22mm self-locking nut that holds the steering wheel on. This nut is to be replaced as it's only intended to be used once. The torque when reinstalling is 59 ft.lbs. Once that nut is removed, mark the steering shaft and the wheel with a marker. A line across both so you can put the wheel back on in the same place. Put the key in the ignition next and turn to the run position. The wheel will then lift off.


Once the wheel is out of the way you remove the 2 philips screw that are in the top of the instrument cluster and carefully pull the cluster out far enough to remove the wiring connectors on the back. There are little levers you raise to release the connectors.





Next lay the instrument cluster down on a towel or mat to protect the face and on the back is most of the bulbs.
To get to the 3 that provide the main illumination at night you have to turn the 2 latches counterclockwise 1/4 turn and swing the back panel up.
The rest of the bulbs are on the back panel.

This car was a 1990 525i, it had: 6 - 1.5 watt bulbs
3- 3 watt bulbs
13- 1.2 watt bulbs
The 1.5 watt bulbs I had to get from BMW, all the rest were available through aftermarket sources.
The 1.5s provide the lighting for the gear indicator on an automatic, the check instrument display, the service indicator and the odometer. These are the ones that are on most of the time.

The 1.2s I wasn't as concerned about changing since they aren't on nearly as much. These are all the warning lights, turn signals, bright indicator etc.

The 3 watts I changed since they are the gauge lighting at night.





I think that about covers it all. Then put it back together in the reverse. Make sure you don't hook up the battery until the very last. Turn the key off after the steering wheel is installed, then reconnect the battery. Otherwise it will trigger an srs code and have to be reset. One other note, On most of the other e34 models the battery is under the rear seat. To gain access just pull up really hard on the front bottom of the seat. While your in there you can look at the bottom of the steering wheel where the copper paste is and spread it around if you have a squeaking problem. A few other notes as well. Some models will
have a nut holding the steering wheel on , some will have a bolt instead. You don't abolutely have to replace the bolt or nut, you can just use loctite on it if needed. Also some airbags will take a t27 torx, some will take a t29 torx.

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Instructions for removal and cleaning of MID (multi information display center) (in the dash unit containing the speedometer and tachometer).

To restore pixels that are not working due to dirty connections.

1.Remove 2 screws above tach/speedo with a T10 torx driver.

2.Pry out upper lip of housing with a flat blade screwdriver.

3.Disconnect 3 wire harnesses in the back of the housing and slide assembly toward passenger side of vehicle. (Make sure steering wheel is down and telescoped fully)

4.Place assembly face down on some type of soft towel and find and remove the wire harness going from the speedo/tach assembly to the module attached to the back. (Black plug at the top of assembly).

5.Push button on the bottom of assembly and slide the module sideways to free it from the front assembly.

6.Locate the five “X” type connectors holding the front onto the main housing. Twist these connectors slightly so they line up with the holes on the housing.

7.Press the four clips (2 on top/2 on bottom) and slide the assembly out through the back of the assembly holding the front clear covering (that covers the faces of the gauges).

8.Now lay the tach/speedo assembly face up on the towel and remove all of the torx screws on the face (about 8-10), this will NOT allow you to open the housing, but it will loosen it enough so you can get a spray nozzle into the circuit board under the cover.

9.Spray any and all connections you with the contact cleaner (non-residue/quick drying/plastic safe). Quickly dry the connections with compressed air (be sure to hold can upright to prevent liquid from being expelled)

10.Spray all holes and connectors and the connectors that plug back into the dash board. Spray the actual connectors in the dash as well.

11.Reassemble the entire unit and make sure it is DRY before reinstalling in the vehicle.

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Required tools:

Small flat head screwdriver (for pushing tabs, etc.)
Small Phillips screwdriver (one that fits the little screws mentioned later in the post, I used a flat head for these screws btw.)
Very thin 3M double sided tape (thinner is better because you will layer it)

Optional:
Some material as alternate for 3M tape, you will see what it needs to be later on in the post
Needle nose pliers, or whatever they're called (for bulbs, but some use their hands so, up to you)


On to the instructions

1. Take OBC out of your car. To do this, you have to push/pull the OBC from the bottom through a hole at the top of the sunglass holder. I find it easier to use a screwdriver (be careful not to scratch the trim) on the sides of the OBC to kinda prop it out, then I push it from the bottom and comes right out.
Below is a pic of the OBC out of the car.


2. Next, remove the back cover from the OBC. The two photos below show the 4 tabs (2 on top 2 on bottom of the OBC) that you need to push in to remove the back cover.





3. Below is the back of the OBC with the cover off.



OPTIONAL STEP, remove the bulbs from the OBC. I did this because when I did another OBC before, one of the bulbs didn't work, I guess since I shook it. I suggest removing them, but it's completely up to you.

4. Remove the display panel along with the circuit board. The two photos below show the 2 tabs (one on each side) that hold the panel and circuit board in place inside the cover. Just push the tab on one side, hold the circuit board back (be careful not to crush anything on the circuit board), then push in the tab on the other side, and wiggle out the circuit board along with the panel. Be very careful when you do this, it will come out, just do it slowly.





5. Here's the display panel and circuit board out of the cover.



6. Next you will remove the cover that is over the display panel. To do this, you have to "unhook" 9 tabs, 4 are on top, 3 on bottom and 2 on the sides (one on each side). The photos below show these tabs.





7. One the cover is off, you will see this. The display panel (glass or plastic I'm not sure, didn't care to check) is held to the white part by a "connector strip" (sorry but I have no clue what that's called) be very careful not to peel the strip off of either the glass panel or the white plastic, if you do, you'll have a lot of fun trying to put it back together, NOT. Just make sure you keep that strip intact, my suggestion is, after removing the orange strip and after bending the white plastic away from the circuit board(you'll see later what I'm talking about here) just set the panel onto the circuit board so that it is hanging between the circuit board and the white plastic where you're working,(again you'll see what I'm talking about in photos later on)



8. This is the orange strip I was talking about. Remember the orientation of it (orange part faces out of the OBC, back/whitish part is facing in) Set this aside for now.
Next you need to bend the white plastic back, away from the circuit board. (it's optional and really not necessary but you can also remove the white little plastic pieces that are behind the orange piece. They didn't bother be since they never got in the way. Sometimes they fall out sometimes they don't. this is up to you)
OK,
1st photo below shows the white little plastic pieces still in the white plastic cover and also I've drawn the direction in which you will be moving the white plastic.

2nd photo shows the 2 little "brackets"(I will refer to it this way since I don't know what else to call it, sorry) that need to be removed in order for you to be able to bend the white plastic back.

3rd photo shows one of the "brackets" removed partially, and rotated. You will need to remove them completely and set aside.

4th photo shows, in blue, the little screws that hold those grey "brackets". You just remove these screws, turn circuit board over, and slide out the "brackets".

4th, in red, 5th, and 6th photos show the tabs you will need to push in order to separate the white plastic from the circuit board. These are a bit tricky. I marked them 1 and 2 for the following reasons,on side 1, it is easier to push the tab and pull out the corner of the circuit board. Next you just pull the circuit board up holding at that corner until it clears the tab in the middle. Then, still holding corner 1, you pull away from corner 2 in order to clear the little tab (as you can see in the 4th and 5th photos, corner 2 has a cutout on the circuit board, so instead of having to pull the tab to the side and pull the circuit board up, you just do as I said, do the hard work on the easier corner 1, then just pull out corner 2. I really really hope all this made sense.)

7th photo shows two metal pieces that are attached to the plastic and soldered to the circuit board. When you bend the white plastic back, these are the pieces that are bending. Be careful to only bend it once back and once back down when you're done, since you don't want to go back and forth and break the thing off. If your OBC is very old, you might want to have a soldering iron ready in case this does break)

Finally, 8th photo shows the white plastic bent back. Circled in red is the area you will be working with.

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Now, the fun part. The whole idea in this fix is to either replace the existing "cushion" with a new one, or make the existing one thicker. The reason for this is that the "cushion" pushes the "connector strip" to the connectors on the white plastic, and this is how pixels are transmitted from the computer to the display panel. Over time, the "connector strip" looses it's grip at some points, thus no pixels showing when you hit the TEMP button. Anyway,
I've posted 4 photos of the work that needs to be done and will refer to them as 1st, 2nd, 3rd, and 4th when writing instructions,

I'm sorry I didn't take a photo of the old "cushion", which you can see in the 2nd photo (I cut it in pieces while removing it)

The 1st photo shows the 3M tape put in place of the old "cushion". The tape is 2 strips taped to each other than taped to the white plastic. You will easily locate where to put the new "cushion" since there are 2 plastic strips, on big one small, running along the edge, as you see in my little diagrams in the 3rd and 4th photos. THE "CUSHION" THAT'S TO THE OUTSIDE OF THE OBC DOESN'T MATTER SO DON'T MESS WITH IT, UNLESS YOU'RE REALLY BORED.

(As I said earlier, if your tape is thin enough, you can simply put a strip of tape onto the existing "cushion" and get the same effect. You will see in the diagrams in the photos that the existing cushions are shorter than the big plastic tab that runs the whole way on the edge. The "connector strip" is at the level of the plastic tab, so ideally you want a cushion just a tiny, tiny bit higher than that plastic tab. If it's too high, it's bad because the circuit board will bow out since it's much tighter at the corners, and you'll probably loose even more pixels. Mine was a bit higher, and when I first connected the OBC to the car, the pixels in the middle were a little bad, but once I put it in it's place, the middle was held together by the molding and everything worked out great, as you will see in the final photos)

The photos might be a bit confusing since I couldn't get a clear shot up close, but you'll understand everything once you actually look at your OBC.
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Well, You're done!!! Once you put the new "cushion" in or "mod" your old one, just make sure it's not higher than that tab like I said and you're good to go. Put everything back together opposite of what you did to take it apart.
Bend back the white plastic and clip the circuit board into it.
Reconnect the grey "brackets"
Put white plastic pieces back in (if you took them out)
Put orange piece back in the right way
Fold back the display panel
Put the little cover over the display panel back
Put the bulbs back
Stick the circuit board and display panel back into the plastic cover
Put the back cover on or go to the button DIY if you need to

10. Finally, enjoy your "new" OBC, with all the pixels.














One additional step. I removed the metal strips (the light contacts) from the back of the white plastic piece. With a small screwdrive I carefully lifted the metal strips off each of the white plastic nibs, then bent the metal strips out of the way. This made it really easy to separate the white plastic from the circuit board.

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