I wasnít originally interested in this DIY because it looked monstrous (pictures of peopleís dash ripped apart with yards of wiring pouring out did not seem inviting at all).
Also the various DIYs on the internet all seem to say different things and tend to leave a LOT of prerequisite details out of their description (like the extra bolt under the glove boxís light that releases the glove box and is omitted in the Bentleyís Manual). So I took the time compiling lots of information from various DIYs and cross referencing them into my own complete DIY. In hindsight, this is just another monster write up for what is essentially a 3-4 hour simple DIY. So don't be scared. Do it!
SOME BEFORE PICS:
My old 7 Button MID/OBC Unit only displays TEMP and TIME/DATE info
Your 11 Button MID/OBC only displays TEMP/CHECK CONTROL and TIME/DATE info
A few key things I will add that I found whiles doing my DIY (these are helpful! If it's one thing you read here, please read these...)
The DIY itself is not difficult. Here is why; 90% of the total work is cutting and splicing wires. The other 10% is removing the old 7 or 11 Button MID/OBC, Lower Driverís Side Panel, Odometer, Glove Box and Turn Signal Stalk. The hardest part was figuring out what the other DIYs I was following were telling me to do and matching their information up with what was actually in my car. Over all itís not Rocket Science at all. When said and done it is not even Gym Class hard.
The 7 Button MID/OBCís Black Connector and wiring is almost identical to the 11 Button MID/OBC's Black Connector and wiring. This has not been said in any DIY before, so I'm stating it now as a fact! They both have the same Black connector with the same wiring layout. Only difference is the 11 Button MID/OBC has a 5 more wires connected to its Black Connector for Check Control features. That is it. Furthermore, both the 7 Button and 11 Button MID/OBCsí wiring is overall 50% identical to the 18 Button OBC's overall wiring. The other 50% will in the new White connectorís wiring that is necessary for powering the 18 Button OBC. So even before you begin this DIY you will discover that 50% of the work is already pre-wired and done for you.
The wiring isnít all that dramatic. DIYs that tell you to buy a mile of wiring and hundreds of splice connectors made me go out a spend money on stuff I ended up returning. I used Heat Shrink for everything and returned about 20 packets of Wire Taps that I didnít even open.
Radio Shack is a cool place. They will have everything you need for
this DIY. Also a quick trip to Home Depot for plastic ties and a long neck Lighter for the Heat Shrink helped.
The Glove Box is actually a lot easier to remove and put back than I previously thought and than most people it make out to be. Itís just that darn hidden bolt above the light that the Bentley Manual never mentions can make it seem impossible if the DIY for this project don't tell you about it.
Upgrading the Turn Stalk really does make a difference. If you are using the previous DIYs you will realize that the writers of those DIY overlooked the fact that BMW made at least 3 different types of E36 Turn Signal Stalks over the years that each ground differently. So get ready for extra splicing if your new BC Stalk doesn't match the ground wire set up of your old stalk. Also as soon as I found the ease of going thru the functions whiles driving with a simple inward push of the stalk it made the entire DIY worth it. Because of that I HIGHLY RECOMMEND UPGRADING TO THE BC TURN SIGNAL STALK
. Since you wouldnít want to be playing with 18 tiny buttons whiles driving.
The ZKE IV Module as a module maybe connected in various places in the Electronic Module Section behind your glove box depending on the year of your vehicle and whatever the hell the engineers at your car's factory was smoking the day they made your 3 Series BMW. As a result finding the little bugger can be confusing because every DIY tells you different. But guess what? They are all right. Your focus is not really the Module itself but the mythical Green/Black wire that actually snakes around the Modules, going in and out of places and supposedly terminating at Pin 15 in the ZKE IV. However, you can tap into the wire itself in some places OR you can splice a fat female connector pin to a wire and find Pin Slot 15 on the Moduleís itself and poke the pin in. Doing it either way may or may not work for you. Even Iím still trying to get it work for me.
Some DIYs recommend 18 gauge wiring, others say 20 gauge wiring, most donít tell you what wire size to buy. This turned out to be important since the Turn Stalk wire that you tap into is 18 gauge and most of the Modules behind the glove box use 18 gauge wires and pins, whiles the OBC unit and Odometer uses 20 gauge. So you will need to buy a small spool of 18 gauge wire and a larger spool of 20 gauge wire.
DIY PREP EQUIPMENT:
Everything you would need for removing the lower dash trim, Odometer, glove box, cutting wires, splicing wires, connecting wires (heat shrink worked the best for me).
Small (about 25 feet) spool of 18 gauge wire; $4.99 Radio Shack. Larger (25 to 50 feet) spool of 20 gauge wire (you can buy various colors-Radio Shack sells a three color spools (red, black, green; 25 feet for each color) in one pack for $6.99.
18 Button OBC-Make sure it comes with both the White and Black connectors with pigtails on each connector.
BC Turn Signal Stalk; make sure it comes with the wiring harness and white connector. NOTE: BMW made 2-3 different BC Stalks that ground differently so if you want you can look inside your steering column trim and see how your current non-BC stalk grounds and buy the BC stalk that grounds similar to that (see pictures below). Also it is good to get a BC stalk anyway because you can easily recycle the female pin connector from your old stalk harness to connect your 18 gauge wiring going to the ZKE IV module and other Check Control Modules in the glove box.
Heat Shrinks, lots of them. For me these are slimmer, better, quicker and more secure that the wire taps.
OPTIONAL THINGS TO HAVE NEARBY:
Pack of 25-50 Small Tie Wraps
Long neck lighter for heat shrinks
White paper tape or Post-It-Notes to identify the end of the wires you splice. Important if you are using the same color wiring for your spliced extensions.
Diagram of the wiring; it is best to make your own drawing (even if you are copying from another DIY) so you will KNOW what you are looking. Use color coding in your drawing if you can.
Camera; Helpful if you forget where things go when itís time to put everything back.
Small Cup or Bag for keeping screws and bolts in.