My dome light on my 2000 RAM doesn't work either. Although mirrors/radio (factory infinity) do. I've followed along various discussions which all seemed to point to the black IOD fuse. So last nite I pulled it but couldn't figure out how to get it out. However, in that process, I ended up shoving it back in and viola!! Dome light came on and I heard a "whirring" noise - not sure what it was - reminded me of a power antenna. Anyway, so I checked operation of dome light - open door, shut door, repeat. Sure enough it worked. So I was happy.
This morning I go out in the dark to warm up truck. No dome light. Radio is working, and didn't even lose my presets although it reset the clock. Didn't check mirrors - but they were working before as it was.
So I must have had IOD fuse out long enough to reset computer. I would guess this also means that IOD fuse is good since I wasn't able to actually pull the plastic cover out to get to it? I'd really like to have a dome light....sheesh. Any suggestions?