Nikon FG no LED light even their is battery and film (used)?

The mechanisms are working ie the shutter, film advance lever, film counter, mirror going up when I shoot and I know how to put it back.

It sounds like there's a problem with the meter display only, meaning that all the metering electronics are working correctly and setting the shutter properly but you just can't see what settings are being chosen.

The FG is one of Nikon's first heavily electronic/plastic 35mm SLR's that was specifically designed for the consumer market. It's not made nearly as well as the all mechanical and metal cameras on which Nikon built its reputation. Personally, it's not a favourite body of mine and I actually sold one a few years ago but am still stuck with two FG20's I'd like to pass on.

You could take this to a repair shop or simply purchase another camera. Depending on how you use it, you may be able to get by without the meter display also. A repair shop may charge as little as $30 to repair this or they may not be able to do it at all depending on if an obsolete part is required.

Personally, I'd suggest getting a more robust Nikon and using whatever lenses you currently have with this new body. If you like automation, something like an FE or FE2 would be only a little larger than the FG but would be much more durable and serviceable.

I'd check out KEH.com for both replacement and repair.

METAL AND MANUAL! FILM FOREVER!