Plugged in a 12 volt heating fan into 2001 300m cigarette lighter port.port stopped working.anyone know why?

Most likely popped a fuse, heating fan is probably drawing to much current so if that's the case, up the fuse by 5 to accommodate the the fan. Say if there's a 15 amp fuse, put a 20 in it's place. Car manufacturers place specific fuses in spots to allow only so much current through the wires and you don't want to exceed this because it could cause a fire. Some people will try a fuse 10 amps bigger which will possibly work but you risk starting a fire. This should do the trick but if not then I would suggest hooking up another cigarette lighter adapter straight to the battery, make sure it has an in-line fuse by the battery. The real question is, why do you need a heating fan? Is the heater not working in your car or not that well? Hope I was some help

Fuse blown The fan heaters draw close to the max capacity of the circuit - yours may even be only a 10A fuse (or even have the wrong fuse in it) A 15A fuse *usually* wont blow - its not advisable to replace a 10A with a 15A but plenty of people do

Heaters use a lot of current. Cig lighers are not meant to supply lots of current. You probably blew the fuse for your cig lighter circuit. Check the owners manual to find the fuse location and then replace it. DO NOT replace it with a higher amp fuse so that you can run your heater. Doing that will be a fire hazard! What you will need to do is run a separate power lead for your heater. But the real fix is to fix your heater system. A 300m should be putting out plenty of heat making the heating fan unnecessarily.

you blew the fuse. You could try fixing the heater in your car.

You blew the 15 amp fuse Stop doing that.