Hi,

Yesterday our 2005 CLK convertible wouldn’t respond to either of the 2 remote keys.
neither doors nor boot.

open door with key blade and car starts fine.

doors will lock/unlock from dashboard buttons.

the 3 fuses listed for central locking are all ok.

tried new fob batteries.

charged the main battery overnight but to no avail.

Has anyone suffered this? Will it be a receiver? If so, where is it located and does the unit have to be coded to the car if Ivan get a replacement?

Are there any steps I’ve missed checking?

 

@Plutoe What does FUUAA mean? - Googled it and doesn’t appear to have an answer.

I may have a quick look at the IR sensor in door handle and check it for dry joints/ corrosion, failing that I’m not sure my i980 code reader will suffice and I’ll get it on STAR /Xentry.

 

Query- does door trim panel have to be removed on a cabriolet to access the IR receiver on door handle?

 

Questions:
1. Have you lost FM radio reception?
2. Does the IR fob unlock the door when you point the fob at it?
3. Is fuse #8 in the trunk blown?

If yes, your alarm siren has crapped out and blown the fuse. The antenna amp is tied to the same circuit. Disconnect (or replace) the siren behind the RF inner fender liner, and replace the fuse.

As you know, the fob uses both radio AND IR to lock/unlock. Losing the antenna amp kills the radio function, but the direct line of sight IR should still work.

 

@CLKDave Thanks - useful info ...I’ll try this today👍


UPDATE - success, the 7.5amp fuse had blown.
replaced and the remote fob is back in action. I suspect the siren module may be dead as it doesn’t appear to sound, if I open the door, I get rapid hazards flashing which I can reset but no sound, ...but that’s a job for a warmer, drier day.

Thanks for your help 😎

 

Just remember that the siren failed once and popped the fuse. It will do so again and you will lose the radio (and fob function). As soon as its warm (over 50), remove the RF wheel and inner fender lining. The siren is down low under the firewall. Unplug and tape up the wiring pigtail until you buy a new siren.

 

This is v helpful Dave, thanks. I'm in the UK with a (RHD) W209 and have this problem. My local garage is telling me that I need to go to a Mercedes dealer to get the alarm removed. Until then I'm just using IR.

I'm ok just losing the alarm - car is hardly worth spending money on now. Do you know what actually needs to be done to just rip it out? Wondering why the local garage doesn't want some easy money!

Thank you!
Dan

 

Dan, this is super easy. First of all, this may be opposite side,, as my car is left hand drive in the US.
1. Remove right front wheel and plastic inner wheel liner
2. Down low under the firewall you will see a black battery/siren unit with a wire going to it. It's about 4" diameter mounted on an aluminum sheet metal bracket.
3. Unplug wire, tape up the wire connector, secure wire pigtail to adjacent structure with tape or ziptie.
4. Optional - Unbolt and emove siren. I think it uses the security Torx bits.
5. Reassemble and put in new fuse. Radio and fob lock function should work, just no siren.
6. Optional - install new battery/siren while there. Should be about 150 USD for a new one aftermarket. Whole job should take about 45 min. Most of that is setup time.

Yes, your indy is passing up super easy money

 

Would you mind pointing me to that fuse? Which fuse box and where?

Thank you

 

for US cars, the fuse is on the LH side of the trunk compartment. It may be the only 7.5A fuse in the block,, so it should be easy to spot. I think it is blue. Fuse #8

 

Hi, I have a US, left hand drive, 2003 CLK430 convertible, W208 and have a similar problem as reported in this thread, as my RF lock/unlock/trunk release is not working and my central locking only responds to IR at the door handle. I've checked all of the central locking fuses both in the trunk, right side of the trunk forward of the battery, and the fuses under the hood as well, all good!

I'd really like the RF unlocking and locking to work. I have no problem with my radio, other than a faded screen and the amp works very well, assuming the radio antenna is also used by the RF locking system. What else can I check to determine the cause of the failure? Where is the RF system/computer located? I haven't gone to my local parts store to check the key fob's RF, but the batteries are fresh and there's no sign of damage. I'll do that later today.

Any comment/help/guidance would be much appreciated!

P

 

I just visited several of my local auto parts stores and no one has a RF tester anymore... It's becoming more and more difficult to fix things.

I did try locking myself into the car by sitting in the driver's seat and pressing the lock button on my FOB. I'm assuming there's also an IR detector under the mirror since locking seemed to work with the fob under the rear view mirror. So with me in the car and the door's locked via the fob I tried opening the door with the interior handle and no alarm, nothing, no sound or flashing blinkers. Could that be a hint that the alarm system is toast? Is the RF coupled with or part of the alarm system?

Is this where the siren/speaker is supposed to be located? Note the nice empty bracket...?



So many questions.

Thanks!