Ranger GEM Diode

I've read a lot of posts about the diode isolation on Rangers. They have mostly been about the year 2000 and up, however. I have a 99 mazda b2500. Do I still need the diodes on this model? I'm also confused with the location of the dome light wire. A bunch of people have said its by the headlight switch, but can I use that wire as the door open input or just as the dome light output? Thanks for clearing this up for me. Shane

MAZDA, B 2500, B 3000, B 4000, 1999, Door TriggerUse yellow/black for the drivers door found in the drivers door harness, and gray/red for the passenger door found in the passenger door harness. Diode isolate each wire. See direct fax document # 1076 for wiring information. There is a single wire available on models with factory security. It is lt. blue/white negative trigger found in the drivers kick in the large harness to the rear.