Side light bulb holder

I keep getting a side light warning failure which come and go, but the bulb is good, however the holder look to be yellowed, I assume that it has a bad conection with the bulb and causing the fault light.

Where can I get a new holder its the type with a long tag that you pull to remove, has anyone experienced these spurious bulb failure warning which come an go at will?

The model is pre facelift.

Cheers All