I have a 2002 Explorer with a double din am/fm/casset/cd player. On the back there are two factory plugs, I think they are a 16 pin and an 8 pin. The 16 pin is used for pretty much all the connections but the 8 pin has two wres connected to it. Is the 8 pin used for a factory amp? I don't remember the wire colors but one draws nothing and the other draws 12v with ignition on. I hooked up an amp and sub to the factory deck for security purposes and it sounded fine for about a week and then out of no where the sub started going crazy! Could this be because of a factory amplifier causing interference? I used the high level input tapped into the factory harness to feed the amp could this be the problem?
The 8 pin probably only has 4 wires, which go to the subwoofer amp which is next to the sub in the rear behind the trim panel. Sometimes the high level inputs on amps will effect the impedance and the factory radio will act up. Also most amps are common ground on the RCA's and the factory radio has floating ground on the speaker outputs. The 4 wires in the 8 pin are shield drain, mono audio +, mono audio -, and amp turn on. The amp turn on is also part of a clip detect circuit and will vary in voltage with volume so cannot be used to turn on a new amp. The audio circuit is a low level differential type and you will need to boost the signal up for the new amplifier. Check out the LOCB at www.soundgate.com under line output converters. You can also use the LOC4 on the outputs of the factory sub amp. Both of these are very high performance and will not effect the factory system.
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Best Regards,
Rich