I'm having trouble locating the diode as well.
I went to a "recommended" independent who did a quick courtesy check of the fuses and connectors - nothing there. When I brought up the diode question, he seemed perplexed, but was willing to investigate at $70/hr.
I am going to keep searching. Anyone out there who can help, please chime in!!
Ken - do you have the part number for the diode. I know many parts are used on different chassis, so this may help us