No power from 12v constant

[jmeeter 10+ year member]

My brother is trying to install a head unit and there is now power from the 12v constant. He only gets power when he hooks it up to the 12v switched. The funny thing is, the original head unit was working perfectly.

Can you think of what would cause this?

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[Digital Designs 10+ year member]

This happened in my girlfriends car too. The ground hit the constant and sparked, and hasnt worked since. I just spliced into the cigarette lighter so I never really investigated farther.

 

[skmfkr 5,000+ posts]

did u check the fuses for it? should have a radio fuse inside the car somewhere

 

[Walled_Taurus 10+ year member]

Run a new one and fuse it. I always found it to be easier.

 

[jmeeter 10+ year member]

Yup we checked all the fuses too.