No power? Dead motor needs this (6,5)
I believe the answer is:
number plate
'motor needs this' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'no power? dead' is the wordplay.
'no' becomes 'number' (I can't justify this - if you can you should give a lot more credence to this answer).
'power?' becomes 'p' (symbol in physics).
'dead' becomes 'late' (similar in meaning).
'number'+'p'+'late'='NUMBER-PLATE'
Can you help me to learn more?
(Other definitions for number plate that I've seen before include "Reg is here" , "Vehicle ID" .)