Hello,

I recently bought an 08 FX4 Scab. I replaced the factory head unit with an AVIC Z110B. I was looking to add a subwoofer in the back when I noticed there was already one back there. However, it does not work.

I have read and searched the fourms, I have read what people have said about the wiring harness and such. Here are my questions:

Ford put subs in the trucks but didn't connect them?

How can I go about connecting mine?

What am I looking for?

Please help and thank you in advance! I apologize for the repetitive questions.

 

When you changed out the HU was there 3 plugs + antenna on the back of the factory unit or just 2?

Did you hook up the sub harness plug to the new HU?

 

I did not install the head unit, however I popped the dash out so I could bypass the brakeline. I will pop out the dash tonight and look. Am I looking for RCA cables?

 

Can you pop the speaker grill off on the front doors? If your truck originally had the audiophile setup (6 disc cd changer, factory sub, etc) there will be tweeters in the front doors right by the inside door handle and a separate midrange towards the bottom. If you can pop off the dash cover around the hu there should be 3 harness plugs that went into the stock hu, the smaller of the 3 only had 8 terminals and that one is for the sub. There should be an adapter harness plugged into it that has rca's and the amp turn on lead. On the sub end under the back seat, unbolt the sub (uses a 10 mm socket) and roll it forward and see if the sub is even plugged in. Also in the fuse panel in the passenger kick panel there is a 25 amp fuse (the only one) that is the fuse for the factory amp on the sub.

 

youll need this smaller plug hooked up to operate the sub...as long as its there from the factory. it should be since you already have the sub. most installers..especially if theyre new or something dont know that this needs to be connected. also you need to wire up a voltage reducer to send 6v to the amp otherwise itll pop when turned on and off

 

Okay, I popped the dash out and these are the only two things I have found. I assume I will need the harness that is pictured above (where can I find it)

Do I need to utilize both of these plugs or just the small one. Can someone take me step by step what to do?

Thanks guys... very appreciative

 

the factory sub one is the smaller one in the right of the pic.

best buy sells the harness. or you can find it on amazon.com...thats where i got the pic from.

but in order to make it work correctly, youll need to wire up 2 resistors to make a voltage reducer. the ford factory amps use a 6v turn on instead of a 12v turn on that the pioneer puts out.

basically it goes: ground---resistor---blue/white wires from plug----resistor----blue/white wire from pioneer. just get 2 resistors that are the same..like 2 1k resistors or whatever. and just plug the rcas into the sub output of the pioneer

 

You don't need to do all that, just run the resistor in series on your amp turn on lead, that simple.

Blue wire from the back of pioneer--->>>---resistor--->>>---both blue wires on adapter harness.

 

Thanks!

Where can I find the harness? I looked on amazon and found the one pictured, however, it said it would not fit in my truck. Is there another website I can go to? What exactly is the name?

Also, so I am only using the smaller plug on the right, the wider plug I do nothing with correct.

Would a 1.5K resister work?

So I can just splice the two blue wires together from the harness with the resister and with the other end splice it into the blue wire from the Pioneer harness?

 

it will fit an 08 f150. their fit guide must be wrong on there. its the Scosche FDK11B. where are you from? i have a bunch left over at my work. id go with a 3k resistor if youre going to do it that way. ive had a few issues with different fords having popping with doing it that way though. thats why i wrote out how to do it with the 2 resistors. never had a problem with the hundred or so fords ive done. but for the most part a 3k should do.

the wider plug is for aux input/sat radio, so no, you do not need to worry about it.

you can try to hit up a best buy and ask them if they have any laying around. some may keep them like i do, or toss em out.

 

If you can't find one locally, you can order it here

http://www.installer.com/item/displa...php?it=70-5521

This place also has a storefront in houston if your anywhere around there.

 

Thanks guys I appreicate it, I'll let you guys know how it turns out once I recieve the parts

 

The blue/white wires from the plug do I splice the resistor in both of them together or would I go ground-resistor-one of the two blue/white from harness. Then the other blue/white from the harness-resistor-blue pioneer wire

 

You can go either way, but the proper way would be to use 2 resistors and create a makeshift voltage divider.

////////////////////////-----------resistor--->>>---ground
Blue pioneer wire---+
\\\\\\\\\\\\\\\\\\\\\\\\-----------resistor--->>>---both blue wires on plug


What you end up doing is sending 6v to each leg of the circuit, but only if each resistor is of the same value. If you have two different values then you will get different voltages on each leg. For example if you have a 500 ohm and a 700 ohm, then the 500 will see 7v while the 700 will get 5v. The factory amp actually uses 5v for the turn on signal but 6v will work just fine.

 

Okay understand perfectly, the diagram helps out alot.

Thanks!