Looking for expert help with instrument cluster issue. See attached for details. Service Manual 8W 40-2

The instrument cluster illumination consists of 7 bulbs. 1 group of 4 covers upper portion and 1 group of 3 covers the lower which includes the LCDs. I have a spare cluster that I'm experimenting with.

The wiring diagram does not match the cluster wiring. See notations on the 2nd diagram. I am trying to find a way to energize the group of 3 without Park or Headlights being activated.

I have tried all combination of pins but can't get them to light. The connector pins do not conform to the diagrams.

Any clarification or correction to what I have observed will be much appreciated.

 

The Crossfire parts catalog and the service manual have so many errors and omissions. You might be better off trying to find a diagram for a Mercedes SLK 320 cluster instead since they are pretty much identical. Even saw a thread where a SLK 320 owner put in a Crossfire cluster in their vehicle.

 

I have the SLK320 Diagram. Same issue

 

Wayne, I don't think that diagram is anything more than a "block" diagram, not intended to be taken literally.
I can't say for sure, but there's so much missing from it, I think it's used as a general guide to understand the rest of the system, and is there only for that purpose - since they intended the cluster to be a "module suitable for replacement only".

It's stupid, IMO, but I really do think that is the case.

 

I have the MB version SLK 320 diagram and it is basically a detailed version of the Crossfire one, however I'm not able to decipher the pin outs. If you look at the diagrams I posted, it doesn't make sense if you look at the various B+ and Gnd. All I want to do is find the circuit for the 3 bulbs that illuminate the lower half of the instrument cluster. Trying to find a solution to make the LCD's visible during daylight with the top down. I know our car electrical network is quirky, but I'm talking a basic lighting circuit, shouldn't be that hard to discover. If I could find a schematic ot the PC board, I could figure it out. That is like looking for the proverbial "hen's tooth". I have a cadaver instrument cluster, courtesy Brian Hoffman, so I'll have to figure out how to disassemble it to look at the PC board.

 

Then you can lead us out of the darkness!

I run with my lights on at all times so it's not a problem for me.