Is there a way to make the horn honk when you lock the car with the remote on a 2005 Mercedes SLK 350?

If you want to reactivate the horn honk feature:

1. Press and hold both the lock and unlock buttons on the remote for at least two seconds.
2. Watch for the hazard lights to flash once. The horn should honk one time.

if a slim jim as not available, try getting the spare keys. or call mercedes before you brake something.

how do you get to the horn
on mercedes 230slk

Mine has just started doing this too; same car. Did you find a solution yet??

Possible motor mount failure.

You can see the belt layout for SLK 350 on page 61 of the pdf:
http://www.billsden.org/fileadmin/media/mercedes/slk/docs/train_slk_r171_intro.pdf

Your lock settings were most probably changed from your remote unit. By pressing both lock and unlock keys together for around two to three seconds you can switch between silent mode and horn mode. Hooe that helps...

If you have your owner's manual, there is a section that will tell you the exact sequence to press to enable/disable the horn bonk. It has three settings, chirp, honk, and off. The chirp is a really quick chirp of the horn. Honk is a longer honk. Off seems to be what you've set.

I hope this helps.

hold both the lock and unlock buttons at the same time.after 5 seconds it should honk.that means it will honk when locked..in the settings on the dash there is the ability to change the headlight delay,etc and it may be in there too to flash the lights,honk etc.

On your remote, hold down the lock & unlock buttons at the same time for 2-3 seconds. This sets it in honk or no honk verification mode.