hello: I've recently acquired a 1996 sl500, nice, fast and very red. It came with two switchblade type single-button remote keys, neither of which work remotely. I've replaced the batteries in both and they still don't work. The keys have a little red LED on them - this doesn't light up either, even when the key button is depressed for 10 seconds. I'm getting depressed too. Could the LED's be burnt out? The central locking system shold indicate it's receiving the key signal by a light under the car's rearview mirror - this doesn't happen either. However, the central locking system works fine manually. Any ideas on how to troubleshoot this, or how to take the remote keys apart to check the guts?
thanks for any help you can offer... Ron

PS: two other minor irritants - the exterior temperature doesn't show in the dash (the LED window is just blank), and while the interior temperature reading does show up, it's dark, so can't be seen at night. Any help with these problems (i.e. how to get at the problem bits so they can be fixed)?

 

if no flashing (very faint on dark place) of red light from the led, then the key is faulty.

check the bulb behind the outside temperature display.

 

alrighty then... should anyone else have this same problem with non-working remote keys, I've managed to fix mine. Both remote keys' switches had broken off their solder points. After re-soldering both work fine. The trick was to take the %$&#! things apart to get at the guts.
Here's the brute force method, since no one seemed to have a better approach:
After I took the batteries out, I pried up around the keyblade using a flathead screwdriver. Gradually the two plastic halves came apart. Careful when the spring on the keyblade pops out - you'll need this during reassembly. After the plastic halves are apart, carefully pull out the circuit board, watching as the micro-switch fall somewhere on the floor (you'll need this too). It is a tiny 4-pin, square unit that attaches up near the LED. You should be able to see the 4 mounting / soldering points where it popped off from. Using your skills at micro-electronics, solder the switch back into place, reassemble (remembering to torque up the keyblade spring so it opens on demand) - the 2 plastic halves on mine went back together snugly. I put in a bit of sealant on a couple of edges to keep it together, but still allow future disassembly without having to cut it open. Since both my remotes had exactly the same problem, I suspect a lot of "dead" remotes have their switches broken off too. My dealer was willing to replace the remotes at over $200 each (Cdn).

Now I need to figure out how to remove my front bumper to make some repairs under there. Can anyone help me out with bumper removal? It seems to be stuck on the upper part - are there clips up there? Bolts? How do I get at them? Thanks in advance.
-R

 

Recently, the key of my 2000 C class doesn't work intermittently. When I press the lock (or unlock) button, the little red light on the key doesn't flash; coming really close to the car seem to help.

I want to tackle the easy fix first. Can anyone show me how to replace the battery in my key. Thanks. VP

 

how many button your key got?

 

Vinnie:
Your problem is most likely dying batteries. Your owner's manual tells you how to replace them. I don't know what car you have or what your key looks like. If the key is like mine (single big button) then you just pry off the lower half of the plastic cover, and voila, there are the batteries. Buy them cheap at Radioshack.

 

owner manual has instructions on how to change batteries --you can get them all most stores ---i beleive they are cr2025's-- if it still doesn't work-- then you will need a new key=by the way you have an infra red key

 

Wow! Thanks for the info. I just bought a 1996 C220 and both remotes did not work, even with new batteries. I opened them up and both button pads were losse in the keyfob. I resoldered them and they are good as new. Thanks!