Dash lights only work when door is open

Hey, I just bought an 88 4x4 Jimmy "Gypsy" last night for $700.00. I bought it to drive during the winter so I can keep my DD safe (2004 Pontiac Grand Am GT). Anyways, the dash lights are very intermittent. They only illuminate when a door is open. When the doors are closed (such as during usual driving), the dash is completely dark at night.

I assumed blown fuse or bulbs until I realized it still works when doors are open, so I''''m stumped!

Anyone have an idea?

Thanks,
Amir

EDIT- Anyone know where I can get an owner''s manual? I bought the Haynes manual, but it''s really just focused on repairs it seems. And, is there a website with some Jimmy information? I know it''s fairly similar to the blazer, but I don''t know just how similar. Thanks again.

theyre pretty much identical.  the interiors tend to be fancier since its a GMC instead of a Chevy (not sure on the differences though since you''ve got an 88)...rims are a different design but identically spec''d...etc...on the 1st gens I don''t think anything was different on the front end like on the 2nd gens.

Check RockAuto for the manual, or look on ebay

No idea on your dash lights.  Electrical problems on that old of a vehicle can be wicked fun