A diode is nothing more than a one way street or a check value. It will
only allow current to travel/flow in one direction and that is against
the arrow. With a high resistance scale selected on the multimeter, the
front to back ratio on a good diode will be 10 to 1. That means you
will get a high reading and a low or close to short in the other
direction. Some meters have a position to check diodes.
BUT you may have to lift one side so as to not see the resistance of the
adjacent components.
Hope this helps.
Garry East TN