I fitted a brand new DAB stereo the other day, it worked perfectly until i cranked the volume to full which resulted in interior parts not working.
Stereo, central locking, clock and roof lights don't work. All other components work fine. No fuses are blown and earths are fine as well.
Any ideas please before i have to call an electrician out.

 

Sounds like its draining power from the other parts.

Have you tried a permanent live straight from the battery. Also give it a good earth too.

 

Upgrade wiring as Glenn said

 

Even with the new stereo not connected the central locking etc still don't work.

 

Have you checked the relays?

 

You have blown the fuse, it's 20A.

Martin

 

I've had all the fuses in the fuse box out to check each one, they are all fine.
Also noticed that when i flash full beam only the n/s works. People keep suggesting an earthing problem but no cigar so far.
Thanks. wish it was just a fuse

 

I know you mentioned it, but it would have made sense. That fuse protects the radio and everything else you mention.

Maybe check you have power at the fuse terminal?

Martin