Cost and future non-availability of the remote fobs vs a master key is part of the reason I've chosen to not use the remote fob I have. I can live without the immobilizer, especially after it gave me some trouble.

All good points. None with which I would disagree.

From a practical standpoint, I can't really justify spending that much on a new fob/key.
Knowing the fobs would soon be NLA definitely influenced my decision. Also, I'm not sure how long I'm gonna keep the E300. I felt 2 working fobs might be a positive as far as selling the car was concerned. Potential buyers can be fickle about such things.

Also wanted to thank "ccrelan" for bringing the fob availability to the fore. Had I waited, I'd have probably "missed my window". I can only assume when the dealer told me, a few months ago, there were over 300 available, he must've been looking at all w210's, not realizing the fobs are different across models and years and not interchangeable. Either way: Thanks "ccrelan"!!

Ha ha! My car isn't nice enough to matter. Three shades of white and a little rusty, but it has it where it counts.


jw2k_fr,

I thought of something else you could do that might shed a little more light on your situation.

One of the nice features on these cars is the additional functions the keys have beyond simply locking and unlocking the doors. For example, if you leave windows and sunroof open you can make them close by using the remote fob or the steel key instead of having to get in the car to do it from inside.

Open up a window or two, and then lock the car with the remote fob or the steel key. I'd try both to see what happens. Anyway, when locking with the remote fob, hold the button down for a few seconds and the windows should close. If using the steel key, turn to the right and hold it until the windows close. If this function fails then it would seem to add to the idea that there is something not right with how the keys are interacting with the car.

To sum up where I'm coming from, I think the remote fob you have may be OK, and that getting another one might not solve your problem.

Wanted to add a quick "follow-up" to my local MB dealer, key/fob ordering experience.
Ordered a new key/fob plus a new master key around 11 a.m. EST on Thurs. 12/30. The fob and keys were not in stock locally. Both keys needed to be cut and the fob programmed. Got a call about 1 p.m. today, Fri. 12/31, from the dealer. My keys and fob were at the my dealer, ready for pick up! HUH!? Can't figure out how on earth they did THAT so FAST. They had to "overnight" it, that's for sure! And I don't know who was doin the "key cuttin and fob programmin" on the other end, but they sure deserve a raise...lol. I figured it would be early next week, at the EARLIEST. Especially considering the holiday week, day before New Years, etc. Don't know where the dealer was located that supplied the items, but even if it was just a county/state or two away, that's still pretty darn good service. I hear a lot, on here, about bad dealer experiences. I can't say I've ever had anything but positive outcomes any time I've gone to my local MB dealer for parts, info or anything else.
Also for your consideration, a few pertinent details in case anyone else has lost their mind, like me, and wants to spend a few hundred bucks on a fob and a couple metal keys for a 25 yr. old car.......
When you order the new fob/keys at the MB dealer, you must provide: a.) the title for the car. b.) the current owner's card/registration. c.) your current valid driver's license. The names must match on all 3 documents.
You will then pay for the items, in full, and MB will process the order. When your new fob/remote/key arrives, MB requires the car, for which it was ordered, be present at the dealer so THEY can check/verify the remote is functioning properly BEFORE they release it to you. No ifs, ands or buts. They won't budge on this detail (understandably so). If you're only ordering metal keys (valet, master, older vehicle without fob) I believe they will release those without the vehicle being present. Other than that, the process was quite smooth and simple.
Thought I'd share my ENTIRE experience in case anyone might be considering a new fob, keys, etc.

Happy New Year!!

Yes, you can get metal keys without the car there, I did that for my old 300SDL and it was about $40.

@gmog220d Thanks for all of the suggestions. Finally had time to go out and play with things on Sunday, this is what I found:

Not sure exactly what the sound of the pump is, and it's difficult to get close to it whilst still reaching the button on the dash, but I think I hear something - it's pretty quiet, even with the seat up - the previous owner said the pump had been replaced, so maybe new ones are quieter? Either way, I can cycle the doors as many times as I like and they always open and close as expected from that dash button.

Exactly...

- Button on dash works to lock and unlock all doors
- key in driver's door lock only locks and unlocks driver's door.
- key in trunk lock only locks and unlocks trunk.

Having disconnected the battery to bring it in to charge, the lock pins feel different when locking and unlocking the doors, which would seem to confirm that the vacuum pump is working. I'm going to go through and check all fuses this week, just in case something is off there.


Nope, so we're back to "some other problem". There appears to be vacuum in the system, and (lack of) pressure appears not to be a problem as I don't hear the pumps cycling all the time.

I'm going to start to read about the vacuum system, I should have some time when I'm away next week. In the meantime, any suggestions very gratefully received.

OK,

Central locking system:
- works, but
- does not respond to keys, remote or blade.

I guess that something isn't communicating with something else the way it should. Bad wire or ground, or failed component? Something a proper scan would reveal or help better diagnose?

Sounds about right, however, I have no idea how to diagnose it further. I'm starting to read up on the vacuum system, but I'm already struggling to stay afloat. I'm going to check all the fuses and then see whether I have a better idea of what to try next

Success!!! Central locking functionality has been restored.
I'm very relieved to be able to report that after testing the fuses under the back seat I found that #3 was blown. This is listed as being responsible for:

The item which jumps out at me is Combination control unit as the rest seems to be about dome lights etc - another issue I had seen but had not yet prioritized compared to the central locking. Replacing the fuse restored the missing link between key fob and the vacuum system.

It's great to have all the interior lights working again, however, now I just need to work out why the rear dome light stays on after the doors are all closed. The low level lights set into the door go off when I press the button-sensor next to each lock 'catcher' (which registers that the door is closed), however, the rear dome light appears to stay on forever, which probably explains why the car needed a new battery and why the fuse blew. For the time being I disconnected one of the wires inside the dome light and have taken the battery indoors as it's too cold to leave it in the car while I'm not currently driving it.

Hey now! That's GREAT NEWS!! Glad you were able to get things working again. Congrats! I know it's an awesome feeling to have success like this, even if it's just a simple thing. Always feels good to have systems working as designed. Now, about that rear dome light.......heh heh

Right on! Thanks for reporting back to us about the solution.

I finally got to drop the car off to have the water pump replaced and spoke with the (locally) infamous "Willy" of Great Neck, and he said that he thinks the fuse likely blew due to an intermittent short in the wiring for the trunk light.

He says that the sheathing becomes brittle and flakes off where it is routed next to the trunk hinges (or something similar) and occasionally shorts out when the trunk is opened or closed. I've already seen the same thing in my headlamp wiring harnesses - it seems that AZ heat has done a good job of frying a lot of that stuff.

I will know more when I get it back next week.