Date registered: Dec 2002
Vehicle: 92 500SEL to 01 E320T and others
Mentioned: 0 Post(s)
Quoted: 3 Post(s)
In the US keys (electronic) and locks are covered under the new car warranty, unless you have a extended warranty that excludes those items. In the US the MB extended warranty covered all those item except radio and self dimming mirrors.
If your car has the "smart" remote, its output is infra-red, (door & trunk sensor) and RF (radio frequency). On my E class there is a reciever in the passenger side headliner, that could be defective.