When I purchased my SLK32 I only received one key fob and it appeared to be broken. I replaced the battery in it, but it still doesn't work. I can operate the central locking system with the key in the door and trunk and also the dash toggle switch.

My question is this: How can I test to see if the keyless entry system works before buying a new key fob/remote. They're pretty pricey and I'd hate to buy one only to find out the onboard system/receiver/actuator etc was broken.

Thanks,
Robert