My smart key will not work at all i changed the batteries it's a 98 clk 320

Battery Disconnect or Replacement Problems

sounds like a bad key and needs to be replaced. you cannot take it out of park unitl the key is rotated.

Car battery might be discharged , or try key lock unlock to calibrate key, hope this helps good luck.

brake switch needs replacement.

Remove the Glove key from the FOB. Inside the slot you can see the little plastic slider. Slider it in and the same time detach the top FOB up and pull it out of the FOB body. After that you will see the battery to replace. Have fun.

trunk key locked in trunk

I would suggest directly to battery, but any charger will work. Just make sure it cycles before leaving it (on and off). A timer on the switch might be a good idea just in case.

I purchased a MB CLK 320 and set the radio frequency and successfully put the freq in memory, however, the radio blinks tthe freq. Is this normal or do I have to enter another key to stop the radio from blinking?
Ed
Massachusetts

This is probably your starter.

Hi, The battery is located in the trunk, under the trunk mat.