2004 SL500: Key won't turn - Steering wheel NOT locked
 

Searching tirelessly to save some money and need help:
Last couple of days there was a delayed start of the car when pushing the keyless-go button. I replaced the batteries in the FOB and now zero response from the key when inserted into the ignition. Steering wheel freely turns and is NOT locked. FOB does not work for any system. All electronics in the car do work. Except the windows are currently stuck and not moving because I cant start the car. This happened, so I took advantage of the down time and replaced the alternator because I was experiencing surging.

Display says "Key Not Recognized".

I have checked the fuses for the keyless-GO system and they are all good. F27 fuse for the anti-theft system was blown and when I replaced the fuse, it blew immediately. I don't have another fuse so seeing if there is another option or if that fuse would actually effect the ability to turn the key?

I am thinking the infrared sensor on the FOB is dead and not engaging the DAS, but why would the steering wheel not be locked?

Anyone else experience this?

I have two keys - one is broken. It happens. Check keys with your phone camera. Look at camera screen while you point key at lens. You will see light flashing when you press the FOB buttons. This assumes you changed FOB batteries. The fuse issue has to be figured out first. Was the Alternator properly installed?

Another key is a dealer item - around $400.

Key not recognized
 

I have a 96 SL 500. I can only guess that a similar recognition procedure is required when replacing FOB batteries. Worth a try. Get in the car. Put the key in the ignition, assuming it has one. Turn the key on and off 3 times. Remove the key. Now try and start the car in the usual manner. Hope this helps. I believe it was contained in the car handbook and I actually had to show the dealer parts guy how to do it!! Some are not the sharpest knife in the drawer, although he suggested he had done this tens of times!!.