Flyinspanner

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

The system is very complicated module wise and your FUUAA will not locate and solve the problem. You need someone with factory or equal diagnostic software. If not live with it!

Flyinspanner

@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.

Flyinspanner

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

CLKDave

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.

Flyinspanner

@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 😎

CLKDave

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.

dpb23

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

CLKDave

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