would someone please post the programming instruction for the 98 S420? this is the 3 button switch blade type key. I did not find anything on this forum. if memory serves right it was something like, hold one of the buttons then lock/unlock driver's door 3 times, then release ...... or something close to this. any assistance is appreciated.

 

im not sure exactly but i think its hold the button, then at the same time turn the key in the ignition 4-5 times i think... im not sure, but u can give it a go

 

Call the dealer, the service rep should know. The 97 proceedure was to push the lock or unlock twice then turn the ignition to position 2