Bought it at auction. When checked it was dead.
Step 1: and When Pulled Apart, Became Obvious Why.. :-)
The switch, wiring and diod got affected.
Step 2: Water Entry Points
Water got inside through holes of the hinge, of back support leg and went under the solar panel glass.
Step 3: Soldering New Switch
Using 2 pole, 2 position micro sliding switch. Make sure to use insulation shrink.
Step 4: Puting It All Together
Was in a hurry and didn't take a picture of sealing the holes of both, leg and its support arm with silicon, on inside and outside of housing, just trust me - it was done, meticulosly.. ;)
As you can see, with switch position "12V", meter reads 18V, on a cloudy day.
Problem solved and fixed!
Thank you, just done my first project