Instrument cluster acting strange with right signal on.
 

I went to replace my instrument cluster on my 1983 500 SL. Upon plugging everything in, I can not get the turn signal indicators to work. Also the temp gauge and the fuel gauge is going crazy with the right turn indicator on. Not sure what is happening but I would be grateful for some help. Nothing seems astray. Thanks.

More than likely your instrument cluster does not have a good ground, which is a common problem on Mercedes cars. To remedy the situation, attach a separate ground wire (brown is preferable) to the back of the cluster (you will find a screw that holds one of the gauges in place to attach one end of the new ground wire). Locate the steering column support where the other brown ground wires are attached and ground the new wire in the same location. Make the new wire long enough to ease the removal of the cluster in the future if needed.

I took my cluster out recently and had this issue after reinstall.

So, I'm in the middle of replacing bulbs thinking I had a bad bulb or something off there causing the issue (one of the fixes when I had the cluster out). My next step was going to be a ground issue, sounds like I should do that as well to be safe.