Pioneer Preimer 940

OK i grounded the unit through a test light and then touched the 12volt to the 12 volt from the headunit and I get a light for a sec then it goes away????? I checked the harness and it is getting a ground and 12volt and i have around 14 volts in the red acc wire. I think it has to be something in the unit itself. But I dont understand how it would be working fine and then when the car is turned off then on it does not work anymore, and then it comes on and off again?   Man this sucks Chandler Martin

On the power wire there is a large black box that is between the unit and the fuse. what is this thing and what is its purpose? Chandler Martin

The large black box is a inline noise suppressor.  You could have a bad suppressor.  If you want to check to see of the suppressor is bad with out cutting your wires you could by pass the suppressor.  This is a little weird but it works.  Take a needle and stick it in the wire in front of the suppressor thus by passing it.  Now touch the hot wire from the car to the needle and your unit should power up.  If this works and your unit stay on you have a bad suppressor.  The needle trick is good because you don’t have to cut your wire and the hole is so small that you can’t even see it once the needle is removed.

check also for a slim white or tan cylinder on the red ( i think ) power lead... Pioneer was famous for using a fusable resistor on this wire instead of a fuse ( dont ask me why )... meter voltage on both sides of this FR and if it's bad cut it out of circuit and install a fuse holder instead....Kevin Gerry

Certified Electronics Technician

MECP First Class Installer

Owner/Installer

Classic Car Audio

since 1979

could that also be why there could be no memory in the deck without running it to the fuse box?southsider