A friend of mine has a 56 plate fabia vrs and has installed an aftermarket headunit in the car but it doesn't power on.  I've checked the voltages with a meter and it's showing 11v at the connections behind the radio, but when i check the battery and 12v socket inside the car they are both reading 14~v.  Would this be a simple fix? Or will the loom have to be pulled out and checked?

Cheers

 

When I installed mine, the red n yellow wires had to swapped from "the norm"

When I installed mine, the red n yellow wires had to swapped from "the norm"

I've already tried this and I also tried the stereo in my car and it worked perfectly

Checked both the fuses?