When I bought my new/old D2, the keys were in a bad state .
The buttons were broken on both, but the lights would light up on one by poking finger in hole.
The other one the lock button worked but no unlock.
I had a close look at it and saw that the unlock button micro switch was broken. It had no switch part.

I looked on Ebay and a person in UK sells new micro switches AFAIR 3 for GBP 5. So I bought 3 switches for a Ford Focus, and they are the same size terminal to terminal as the LR ones. ( luckily!)
The job then is to remove the old switch from the board and it is surface mount. On mine it just came apart with a jewellers screwdriver, so I polished up the contacts and then soldered the new micro switch in place with the aid of a strong light and magnifier.

Fitted my blades and boards to new covers from China which included new batteries and voila 2 keys that light up.

Next step is to ascertain why the remotes do not work. They both start the car so they satisfy the passive immobiliser. Someone suggested that the receiver in the car roof may be broken so maybe I will get one of them. I might wait until I am able to afford a Nanocon Evo.

Regards Philip A