Hello I would appreciate any help you all could give me. I have a 97 SL320 and it is good condition but about a year ago I dropped the key and it fell into a bunch of pieces. So I ordered a new one from the local mer store. The old key still worked but was just in pieces and the keyless did not work. a few months later I went out to my car and it opened and cranked over but never fired up. I puilled out the old broken key and it started right up. So I have just carried the new key to open and lock the doors and then starting it witht the old key. I was telling my son about this and he said that was silly and called the mer store and they told how to program the keyless entry to the new key by unlocking the car putting the new key in the switch and holding the keyless button in for a little bit. Well he did that and the keyless still worked and then both keys started the car just like they should have. I drove my car home went out to leave the next time and it just cranked and cranked with both key and will not start. It sounds like its not getting any fire. also if it helps to figure this out the power windows roll down about 1/2 and inch to help shutting the door for the top, when this all started it quit rolling down teh 1/2 inch and when I open or close teh door hangs up a little on the top.

Hi David,
on your '97 SL, the flip key performs two different main functions.
1. It provides access authorization when you press the button.
2. It provides drive authorization when you insert it into the ignition lock.
The second function is totally independent from the first. Even if batteries are removed from the key, the chip in the key is recognized through the black plastic ring on your steering lock as a valid transponder and the car should start even if you didn't unlock it with the remote.
Therefore is a key that doesn't start the car faulty and needs renewal unless it's key-track was disabled by the dealer for anti-theft purpose.
Get 2 new keys. Nothing you can do otherwise.
The window problem is not related. It's a microswitch in the door lock that usually causes this fault. You can adjust it! Check it out.
All the best,
Dokta

Hello Thank you so much for the guidance I will work towards that direction the local dealer was telling us that we needed to replace the whole ignition switch and keys with it, and we were sure hoping that would not involve all of that. Thank you again for responding to my question

One more thing...
On your "97 SL, the drive authorization is indicated in the inside rear view mirror when you start the car. The green light says "OK" whereas an alternating red and green light indicate "no authorization". So I take it that this is what you see when you roll the engine??!!
Otherwise there's something else wrong but the keys!!
All the best,
Dokta

i didnt know about the greeen or red light ill look for that but its on the inside on mirror and i guess it doesnt mater that this is a USA model or not I noticed you were from bahamas, which must be nice. Love teh weather down there. well thanks again. David

Thank you for your help I went home and tried looking for the light and see a small dot on the upper right hand corner of the inside mirror. If that is the light it does not flash at all either when getting in the car or as I crank the carr over to start it. Thank you David

That's what happening to my 95 C280, what would have cause this "No authorisation"? but it resets after 10mins and performing as normal

I have replaced:
1. HFM control module
2. Keys
3. Car Battery
4. Voltage regulator
5. IFZ control module

what else could have caused this?