Mazda b2200 dome light wont work when doors open its a king

I have a 1992 mazdab2200 and when I open the doors the dome lights do not turn on I took out and cleaned the door switches its not those. The switch to turn them on manually works but in the on when doors open mode nothing the truck was doing this a while but randomly would work what is broke? Iv never been more stumped in my life ever!!! The floor boards are pretty beat but I don't believe it caused this I'm thinking under the hood a ground is loose please give your opinion as this is driving me crazy the frame and floor bords have 35 percent remains litterally! Maybe a wire got rotted.i have a 98 frontier puts these mazdas to shamr but reliablity there eqwual besides rust that is nissan!

I believe there's a separate wire for that it could be shorted out or like you said rotten through

Are you sure the switch is not broken? It should switch between Off, Auto, and On. Perhaps the auto setting is corroded, grounding out, or something of that nature.

Ok in short if your door sensor is good and clean and grounded and when the door opens the dome lights or light(I own a cabplus) your dome light is probably the problem not wiring or grounds.Those switches for the ON,DOOR,OFF wear out especially the rear view mirror switch.If the switch is loose at all it probably has broken a contact point on the rear view mirror and dan atkins has these brand new.I know this first hand and have owned my b since brand new in 1987! You did not say reg cab or cabplus but normally the cabplus have rear view switch is toast and or bulb contact center dome light is bad,and still have my center dome works fine bulbs contact points needed adjust to make bulb burn bright.Hope this helps.

You need a test light or better, yet: a digital multimeter, $11.49 this week at Sears and a wiring diagram so you can actually test out the door switches and check out the 3-position dome light switch.

So far all you've really confirmed (by your post) is that the bulb is good.