Fuse is ok, I have a donor car with good blower and blower regulator. Switched those with the current e320 and the blower will run with key on engine not running. With engine running blower goes from high to very slow after 20 to 30 seconds. If you turn off the blower switch for 5 minutes and turn it back on it will run for 20 to 30 seconds. Blower is on high, not auto