Yes absolutely, you can become an aircraft technician if you are colorblind. The European Union Aviation Safety Agency (EASA) even has an FAQ for this in which someone asked "I am a colour-blind. Does this prevent me from getting a Part-66 licence or exercising my licence privileges?". The answer states that
Regulation (EU) 1321/2014 does not require any medical examination before applying for a Part-66 licence.
Note that you need the EASA Part-66 licence in order to work on "Maintenance on aircraft structure, power plant and mechanical and electrical systems" etc.
Therefore you do not need to see color to become an aircraft technician.
The same applies for the FAA in the USA.
If you google around a bit, you will see that color-blind aircraft technicians share their story on relevant forums.