I have a 2005 Nissan Murano, when the AC or Heater is running it smells like ****. Any solutions?

Yes you need to change your in cabin filter. Wal-mart sells them for around 15$ if you buy the one from Nissan it is around 50$. You will find many recommendations for self install that say to take apart the dashboard and 7 or so screws. Skip that the easier solution is to slide out 2 hinge pins that hold the glove box in place they are located on the underside of the glove box. You will find there is a string that holds the detached glove box so don't yank too hard once the hinge pins are out. Support it if possible so it's not dangling in mid air. There are some clips that cover the flap that holds the filter in place a flat screw driver will make prying those easier. Note orientation on uninstall of old and reverse procedure with new filter. Reinstall flaps/clips then glove box. Viola Saved yourself 129$ dealer install..

Ok, it could be your condenser has mildew or your cabin air filter requires replacement.

Change the cabin filter