The display works correctly other than it is not backlit. I pulled the instrument cluster out and replaced the bulb (what a pain!) and it still does not light up. Any suggestions?

On most of these, the bulb is soldered to the board. Did you do this?

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

No, I didn't realize that. There was a standard dash bulb recessed in the back of the display. This is what I replaced. I did not take the cluster out completely. I believe I have the correct bulb for this also. (I thought the supplier had sent me the incorrect one). I've read in the posts that it is helpful to take the steering wheel off to remove the cluster. I don't think I am ready to tackle that yet. If you can give me a step by step on removing the wheel, I may want to try. If not, I may be able to slide it out if I remove the wiring harness(s). I could not figure out how they unsnap from the cluster.

Your help is very much appreciated.

Thanks

Joel

MB owner of 2 weeks and counting...

bainjs:

My display stopped being illuminated right about the same week yours did. Must be that the bulbs only last 18 years

Do I have to pull the cluster or can I get to it some other way? Or might there be a fuse blown somewhere? (Wishful thinking, I know.)

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Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic

Having recently changed out a LCD display on my 87 SDL:

If you have a telescoping steering wheel move it all the way out, pull the instrument cluster with the appropriate hook tools.

You can then tilt the cluster upward and to the left or right, using a short or stubby Philips head screw driver you remove the two screws holding the LCD display in place. First the screw on one side the tilt the cluster the other way and get to the second screw on the other side. The screws are approximately three inches apart one on each ear of the module about one inch to the right and left of the electrical connector. you will be holding the screw driver in your hand with the tip facing towards you. You will in essence be attacking the screws from the inside of the dash perspective. It’s not as hard as I'm describing! with the two mounting screws removed you can grasp the electrical connector and pull the module back towards the dash about three inches and it’s free! unplug the electrical connector.

For the next step it is important to have the proper tools as the screws are very small and the heads are easily stripped, not so much during their removal but as you rescrew them back in during reassembly. You want the largest tip that will fit the screw head as a too small tip will move around and slip out of position and there is not much meat on these little screw heads. I used a screw driver that I had bought at SEARS for $2 that I checked for a perfect fit. I just brought the module with me and went through the ones they had in the rack!

The module is held together by four very small Philips head screws, remove these four screws and you can pull the plastic housing apart exposing the circuit board. I have examined two types of innards to these modules : the older type uses a full size circuit board with discreet components and the newer type has a much smaller circuit board with VDO's proprietary surface mounted IC chip. But there is a separately mounted "grain of wheat" bulb on either. For the old style unit you can see the bulb near the back of the LCD itself, on the newer unit once you open the case the main body has only four wires traversing it, the circuit board is much smaller and mounted vertically at the front of the case, you have to remove two additional screws to free this smaller circuit board.

Once you gain access to the bulb you remove it using a soldering iron and replace it and re-solder the new bulb in its place. These very small bulbs "grain of wheat" are available at Radio Shack at about $1 for two. I don't have the part number but you can just take your module with you and compare to get the right one just make sure its 12V. Hey at least you don't have to jack up the car and crawl underneath to do this repair, Good Luck!

Mine was only 8 years old. Luckily, the bulb for the temp display is one of the standard 1.2w dash bulbs with the blue housing for the C280, however, I did have to remove the cluster to get to it. To make matters worse, the first bulb I installed was bad also. I ended up removing the cluster 3 times before I got it right. I'm getting pretty good at yanking it out now.