Part Number: 201 540 0845

Most MB parts shop call it a relay, some call it an idle control relay, and some say it could also be called an Overload Voltage Protection Relay (OVP). What exactly is this called? And can I use it in my W126 (280SEL)?

Secondly, what is the primary function of a relay?

Thirdly, can I still drive the car if a relay (say, the idle control relay) has failed?

And lastly, what are the typical symtoms of a faulty idle control relay?

Hope to get my data cleared up, I'm getting rather confused. Many thanks!

Mervyn
W126 (280SEL), 1983