Good evening all

I have a 1986 Mercedes 300 SDL with 280,000 miles on it. I decided to pull the cluster to install a spare unit. My speedometer hasn't been working since I purchased the car. I installed the spare and there was no change to the speedometer.

My big question: How do you know the proper alignment for the round black plug that fits on the rear of the unit? I noticed that some of the dash lights were on that had not been on prior to install.

After removing the plug several times, I also notice that different variations of the turning of the plug and install would change which warning light, gas gauge, and etc. worked.

So now I am completely confused as to which is the proper alignment. HELP Someone....

Ron

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