Hey Guys,

I used to have two problems with my OEM sub on my 2005 F150:

1. Sub crackling during songs and even when unit is off. Kind of like a buzzing and such.

2. Loud thump on startup.

Per Ducati's suggestion I built the 5V reducer with a .1uf cap on one side and three .1uf caps on the other. This got rid of the sub thump.

Then I heard from a guy at CC that a bad ground is usually the problem of sub crackeling. But to test it and see if it's the sub, disconnect the red and whites and see if the sub crackles. I did this and didn't have any crackling for awhile. So I assumed my problem was that I had taped the red and white connectors together (side-by-side) to prevent ratteling and was thus getting interference on the grounds (outside gold parts of the connectors). So before taping them together to prevent ratteling, I went ahead and taped them separately to cover the gold ground area of the RCA connectors.

For a week I've been crackle and thump free. Now I'm getting a crackle from the sub again, however no thump. I'm frustrated as all heck and am about to give up completely on this dumb thing.

Can someone give me a suggestion or help...please.

Thanks again,

Duke

Here is a diagram of my current wiring:

 

I must be speaking another language because nobody seems to be able to know what is needed to fix this.

Duke

 

Is the crackle more of a static or humming? If its more of a humming sounds to me as there might be wires touching some place. Also double check RCA cables mine did this.. They could be in backwards..

 

Tough call on whether it's static or humming. It'll change pitch at times actually.

The stock OEM sub and amp harness has a plug which has 4 wires going into it. All 4 wires run across the bottom of the plug and I forget the colors of the wires.

The Metra harness has two wires on the top row (not even used on my OEM plug) which run to one of the RCA cables. This makes sense that just in case you have two rear subs, which I only have one. Then the Metra harness has 3 wires on the bottom not four like my OEM plug!

The wire that is on my OEM plug that doesn't have a recieving wire in the Metra plug, is a black wire. So now I need to find out what this black wire does and see if it's the cause of my crackeling which causes the sub to sometimes not work at all, crackel or work fine.

Let me know if you guys know what this wire on the stock plug does.


Thanks,

Duke

 

I found this diagram which shows the 4 wires for the 05 F150 audiophile plug. The black wire marked "drain" is the wire that doesn't have anything on the metra harness which connects it.

Does anyone know what the "drain" wire does and what, if anything, it should be connected to?

Duke

 

Well I feel like I'm having a conversation with myself.

I called Metra and talked to them about it.

Apparently the black wire from the OEM harness that doesn't connect to anything is the Shield Ground Wire. This wire normally isn't needed but some OEM amps and subs can be "touchy" and need the extra ground.

I will ground that wire later tonight and see if that makes a difference.

Duke

 

if you can detect a slight pitch difference, then i would say it is indeed the ground. my guess (without knowing the OEM head/amp/sub setup) would be to locate a more solid place for the amp to ground to and replace the wire to a heavier gauge.

 

Wouldn't an OEM woofer problem be covered under the warranty on an '05? Hard to diagnose a stereo noise/feedback problem without hearing it myself and seeing the quality (or lack there of) in your wiring modification. My guess... it's the Flux-Capacitor.

 

Well I grounded the black wire coming from the OEM harness and so far so good (knock on wood). The sub hasn't crackled nor cut out and stoped working. I'm so glad this project is done.

This thread will be a huge help to anyone with a Ford vehicle and OEM sub. This gives the wiring diagram for the sub, the correct way to reduce voltage from the aftermarket headunit to prevent sub thump, and the correct way to make sure the OEM sub doesn't give you performance problems.

Duke