"Roger Long" wrote in
:

Did I blow the diode by hooking up with reverse
polarity?


Yep. The diode only conducts when the field in the coil of the relay
collapses, when you turn the power to it off. The diode is reverse biased
(+ power to its banded cathode end, - power to its anode) when the relay is
energized. You had it connected up backward, zapping the diode to a short.

Oops....

+12-------coil----------12
| |
--|--
band noband