Brand new Pioneer (and an older Kenwood) that won't power on...I have 12 volts at the stereo connector..any ideas? Ground is good....otherwise I wouldn't have 12v at the connector

 

did you connect the illumination wire ??? because that can cause problems like blown fuses and shorts.

 

The yellow? Yes, the yellow constant supply is hooked up.

 

You need 12v at both the yellow and the red wires (aftermarket color scheme). Power for the yellow wire often (older models anyway) comes from a fuse under the hood. The red wire comes from the "radio" fuse under the dash and it should switch on and off when you turn the key on and off.

Many aftermarket units have a protection circuit so they will shut down / not power up when there is a short detected in the speaker wiring. Check all speaker wires for continuity to ground, they should all be open circuit. Each of the eight speaker wires out of the unit goes to one end of one speaker ONLY. Do not connect any speaker wires to each other or to ground.

 

The illumination wire he was referring to is Orange. On certain years, hooking up the illumination wire will blow out part of the electronics in your dash.

 

Thanks mk378! The yellow only had 4.5v, found 12 off the fuse block and we are good to go!