little black box on hu yellow wire?

This really isn't an important question but I'm just curious. On my yellow power wire for my headunit there is a fuse and also a little black box with what looks like a coil of some kind inside. Anyone know what the purpose of this is? This is on a Pioneer HU.Pioneer DEH-P980BT, Zapco DCREF1000.4,Pioneer TS-C520PRS, Adire Extremis, MTX TA91002, TC Sounds TC-3000 15"

isnt the yellow on pioneers the ignition turn on lead? well anyways the coil is probable a fuse holder AGU that will prevent any damage to the deck when it draws more than the specified amps. Pioneer - red (constant 12) yellow (ignition) but if its an older one, th eonly thing i can think of is sony wiring. they list their wires as red- ignition yellow constant 12.

It's just an RF filter... a choke, that only allows the DC necessary for the deck to function, through, while keeping the RF and ancillary noises in the electrical system, out. You can remove it if it bothers you, but you'll probably end up getting more noise than it's worth. It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

I'm pretty sure yellow is 12v+ constant and red is switched.

coppellstereo wrote: I'm pretty sure yellow is 12v+ constant and red is switched.

yah definately every deck I have seen it is Yellow = constant and Red = ACC

Sometimes the "little black box" is NOT just a filter, it is a DC to DC power supply and must be used for the head unit to operate properly.  What is the model number of your HU?Support the12volt.com

it's a 980BT, just like my sig says...sorry couldn't resist.Pioneer DEH-P980BT, Zapco DCREF1000.4,Pioneer TS-C520PRS, Adire Extremis, MTX TA91002, TC Sounds TC-3000 15"