Contribution d'origine par : jayeff ,
Hi @greatlakeruler , The amp may need to be "triggered on" from the radio. Here's a [http://www.modifiedlife.com/1998-ford-expedition-car-stereo-wiring-diagram/|link] to the radio wiring harness wiring colours. You need to get to the harness at the back of the radio and check that there is power on the TWO 12V+ power wires and of course that there is a good earth (ground) as well on the appropriate harness connector wires. The switched power is the one that comes from the ignition key being operated, at least to the accessory position. If there is no 12V+ on both wires, (with the ignition key in the accessory position for the switched power wire), then you'll have to follow it back to find where the break is. Same with the ground. You will notice that there is a wire from the radio to the amp called a trigger wire but I'm thinking if the radio doesn't turn on then the amp won't be turned on either from the radio.