Im having problems with the pickup selector of my guitar. Everytime i switch PU's the sound flickers and sometimes dies down. I think it has something to do with lose contact inside but im not sure. does anyone know the reason for this? how can i fix it?
faulty selector probably. check for some loose wiring.
Ibanez RG321MH (Air Classic/Tone Zone)
Fernandes Telecaster (Twang King/stock bridge pickup)
Blackstar HT-20 (Scumback 55 speaker/ Tung Sol tubes)
TC Electronic Nova Repeater
Lava Cables Clear Connect, Soar and Mini ELC
sorry for this noob question but how does a loose wiring look like? i mean, how would i know if its a loose wiring?
If you google for 'wiring diagram ***' (where *** = your guitar) that should give you the diagram for your guitar. If you're happy using a soldering iron (but from your 2nd post I doubt it ) then you can just open up the electronics cavity on your guitar and re-solder any dodgy connections. It might be the connections just need a spray of WD-40 or similar.

The electronics locations depend on your guitar and could be in the back or under your scratchplate etc. This might entail removing all your strings and re-stringing them.

If you're in any doubt about any of this get someone with experience (guitars/electronics/both) to show you what to do. Failing all these, take it to a guitar shop and have a technician look at it.