Jump Start Caution?

[blassberg]

Apparently you can not have the key in the ignition while you are jumping the car because it can damage/greatly affect the operational qualities of the key itself. So unplug it, wire your car up to the other car's battery and THEN start the car. Hopefully this is something we can all avoid, but who knows?

http://www.mercedesforum.com/m_18597/tm.htm

 

[jberks]

I would imagine if you have a completely dead battery and just stick on jump leads you coul get a current surge which, if any circuits are active, could do some damage, but the same applies if you disconnect and reconnect the battery. There is some stuff around alternators and jump leads too but I've never fully understood the implications.