1983 500SL will not turn past position 1 with key.

[nh500sl]

The steering wheel will unlock and Indinget power to the stereo. I’m assuming it’s a problem with the tumbler. What is my next step from here? Thanks.

[rowdie]

First don't turn it to off again! It may stick there and you are screwed. Leave it in position one and disconnect the battery. Read the manual for procedure to remove the tumbler. https://www.startekinfo.com/StarTek/outside/11883/?requestedDocId=11883 380 or 560SL will be the same. Section 46-640

[97 SL320]

I'd disconnect the battery as not to drain it. Next I'd try to remove the ignition switch and see if the key turns farther.

Find instruction on how to take the lock cylinder / tumbler ( where the key goes in ) out. Generally, lock cylinders need to be turned to a certain position then a pin pushed to allow the cylinder to be extracted. Some cars need a trim ring to be unscrewed. If for some reason you remove the key and can't get the cylinder to turn again, destructive methods need to be employed to get things apart.

At this point looking for worn / broken lock parts is the next step.