Ford Sport Trac "Adrenalin" Audio Upgrade - Success! | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Ford Sport Trac "Adrenalin" Audio Upgrade - Success!


Elite Explorer
June 2, 2000
Reaction score
City, State
Year, Model & Trim Level
'05 Sport Trac Adrenalin
We start with an upgrade to the head unit.

"Easy enough" one might say, but I’m not known for doing anything “easy”…

First our history lesson: The Adrenalin sound system is a Pioneer 6 disc head unit that was “cutting edge” when it was designed in 2002 - even when this unit was installed in this 2005 Sport Trac, it was still pretty good.


The Pioneer head unit has three connections: Antenna, Power/Signal and Amp/Subwoofer which go to an amplifier mounted to the rear of the cab (behind the access panels, behind the folding seats.) The Pioneer Amplifier is 6 channels: Front Left/Right, Rear Left/Right and Subwoofer Left/Right even though the signal from the head unit is a monaural subwoofer.




The output of the amplifier is sent to 4 in door Pioneer 6x8” speakers and the Ford Audiophile 8” dual voice coil 4 Ohm subwoofer (in a fiber filled plastic box under the driver side rear seat, or on the back wall).



- My original complaint was the lack of RDS - I’m a big fan. There are also No External Connections for audio, No USB, No iTunes Tagging and No iPhone /iPod controls. In 2012 this seems almost inconceivable and downright barbaric.

The most desired features were HD radio (digital stereo with no subscriptions), USB port and iPod control and RDS would be a bonus, but not a deal breaker. For this we chose the JVC HDR70 Receiver from Crutchfield Audio ($139.99 complete with install kit and harness, shipped free $20 off with reference code: pe3du-uud6u-9tuyh).

Since the main harness is speaker level outputs and power this begs the question “what happens to the amp?” since you cannot provide speaker level input to the amplifier without causing SERIOUS damage. Also, there is no Amp/Subwoofer harness provided. A quick call to Crutchfield Tech Support reveals that the intended installation is to bypass the factory amp or run new speaker wire to each door. Not an option. Why would I give up a 510 Watt 6 channel amplifier?

So, off I go in to ever so familiar territory - “the unknown”.

Here’s what we know; I will need to modify the existing install harness to include:

A custom +5v remote amplifier turn-on lead (JVC is +12vdc, like everyone BUT Ford).

Custom RCA jacks adapted to the speaker level lines to provide no more than 2.5vdc input to the amp.

I will add a case ground as I never trust the “ground wire” to be anything more than a power return.

And we’ll also want to remove any pins/wires that aren’t being used to make things less complicated.

So, the reason there is no kit available for a direct bolt in is the 5v remote line - this will be custom and SLICK.

Parts List:

1/8” heat shrink cut to 1” lengths (~2 ft) - cheapest in bulk 4 ft
1/4" heat shrink cut to 1” lengths (~1 ft) - cheapest in bulk 4 ft
Vehicle specific pigtail
Head unit specific pigtail
Solder - forget tin! Go with rosin core lead solder.
Soldering iron
Electrical tape
Wire strippers
Wire cutters
LM7805 +5V Voltage Regulator (Radio Shack
Assorted wire
1 or 2 RCA cables (each has 4 connectors - 2 red, 2 white - Get a video cable and use the 2 yellow for the subwoofer!)

All lines are stripped, twisted, soldered and heat shrinked for a maintenance-free and professional finish. This allows us to use this cable between the factory harness and the new head unit without cutting the factory harness - this is very important due to the level of sophistication of modern vehicle electrical systems.

RCA ends are easy enough - you probably already have 2-3 set of these lying around from previous stereo installs or electronic purchases - if not, the can be had for under $10 at nearly any store with electronics.

The things to remember:

Red is Right
The solid color speaker wire is (+), the stripped matching color is the (-)
The RCA jack (+) wire is USUALLY the same color as the jack, and the (-) is the shielding


Now, what about the +5v? Easy, we are going to use an LM7805 +5V Fixed-Voltage 3-Prong Regulator from your local electronics store (~$2) and wire it as follows:

Pin 1 (Input) to 12v head unit remote (usually blue with a white stripe)
Pin 2 (Common) to 12v Ground (usually black)
Pin 3 (Output) to the +5v (usually blue with a white stripe)

In this JVC install there is a LARGE amplifier heat sink on the back of the head unit that will see minimal use since we aren’t using the onboard amp. This is tapped for an M4x8mm long screw - this will be used with a washer and “Arctic Silver” heat sink paste (TOTAL overkill) for our regulator.



Follow the directions provided with the dash adapter and wiring harness.

Main harness is too simple, just connect the two and it's done.

Secondary harness with the +5v remote and the subwoofer? Insert the pins in to the respective slots (+5v pin 5, SW (+) pin 4 and SW (-) pin 3) and use electrical tape to secure.

You could go one step further and either get a male pigtail to splice (Easily removed, but expensive) or cut off the factory connector and solder the wires (most secure, least desirable).


Works great, looks great, and sounds even better!



Thanks to Crutchfield for your great service and Crutchfield Technical Support (Ed) for excellent support!!

iPod tests 3/14/2012 - Like this JVC HDR70 even more! Full iPod Control with USB!

"Near perfect match" for Ford dash lighting using "Buttons Color": , and "Display Color":

iPhone tests 3/17/2012 - Full iPhone Control with USB (Audio), need to try phone functionality

Cellphone tests 3/17/2012 (using 2.5mm front and rear panel inputs), analog audio is "Meh", but works!

Bluetooth Module is available, may have to get one for testing...

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!

Nice install, I've been trying to figure this out for a long time. Let me see if I've got this straight.

-You've by-passed the speaker level outputs from the new HU...those wires terminate and aren't connected?

-All outputs to the amp are via RCA outputs, splitting each plug into a +/! and splicing into the existing wiring behind factory HU?

-The only wires connected to the new HU are power, ground, the blue power antennae power wire, and separate radio antennae wire?


I know this is an old thread but is there anyway to get the pictures to load? I cant see any of them but one.

I tried to follow your awesome install!

Really nice install. I tried to follow your install with the help of Crutchfield but with a Pioneer HU. My only issue is that there is a small pop or click when I change station but not when I have a CD installed and change tracks. Would you have any ideas for me.

Checking my old photos to see if I can recover these images... :(

Checking my old photos to see if I can recover these images... :(

Would love to see the images. I am going to do the same thing, on my 2004 with the Pioneer stock system, this weekend.

Would love to see those pics as well if you can find them. Thanks!

Ok, so I decided to tackle this. The information provided by “Fredness” was super helpful, but without the pictures, it made the job a bit more difficult to re-create. However, after some work, I got it!!!

I went from this:


To this:


Things need to install a new head unit while retaining the stock speakers, sub and amplifier built into the Adrenalin:
**You will need an aftermarket stereo with 6 pre-amp outputs. Front Left & Right, Rear Left & Right, and Subwoofer. (I used a Kenwood Excelon x-799)
**Harness needed – Either 70-5519 (What I used in these pictures) –or-70-5517. Either one you use will require modifying the smaller 8-pin (Subwoofer) connector.
**5v step down converter (Axxess AFDI-5v)
**RCA connectors - (Either use some old RCA cables or you can order some on Amazon like i did. (Bluecell Screw Terminal Male RCA connector is the product I used)

Here are the stock wiring harnesses behind the Adrenalin stereo (Mine was butchered by a previous owner. I found and fixed a couple that were loose and some that had NO casing over them whatsoever! - not even electrical tape!):

16-pin main speaker & power harness:


Rear of the adrenalin radio:


8-pin Subwoofer and amplifier "turn on" lead (When you wire your connector up, the solid green and solid black wires on this harness will NOT be used):

So, here is how I wired it. It sounds a bit better with the new head unit, but the ability of having Bluetooth, Pandora, hands-free calling, RDS, etc. is sooo worth it!!
This really wasn’t that bad of an install. If you have installed aftermarket stereo’s before, you can do this.


On the large 16-pin connector included with either of the Metra harnesses:
- Wire these as RCAs – Speaker outputs – Connect directly to the pre-amp outputs on the new head unit. (Just follow the labeling on the harness’s wires. They do in fact correspond to the correct speakers.)
o Green – Rear Left
o Purple – Rear Right
o White – Front Left
o Grey – Front Right

- Tie these into the new head unit’s stereo (Just match up the colors.)
o Red – Switched Power
o Yellow – Constant Power
o Black – Ground Wire


5v step down converter (Axxess AFDI-5v) – This will be wired inline from the new head unit’s wiring harness to the 8-pin subwoofer metra harness.
- Blue W/ Red stripe – 5v output: to 8-pin metra connector which goes to the Stock amp
- Black – Ground
- Blue w/ white stripe – 12v input: to new headunit’s harness


On the smaller 8-pin connector (Subwoofer) included with either metra hardness:
- You only need 3 wires on this connector.
- As Fredness stated: “Insert the pins in to the respective slots (+5v pin 5, SW (+) pin 4 and SW (-) pin 3)”
- **Pin 5 will splice into the output of the 5v stepdown converter. (i.e. you will be sending 5v to the stock amplifier to turn it on.)
- Disregard, remove, or tape off any other wires on this harness (This includes pins 1 & 2. You will not need these.)
- See labeled picture from my install

8-pin labeled.jpg

On the new aftermarket stereo’s wiring harness, discard, tape off, or get rid of the green, purple, white, and grey wires that correspond with the speaker outputs. They are not needed if you are using the stock adrenalin amplifier. (These are amplified through the new head unit which will damage your stock amplifier on your adrenalin if used. This is why we instead wire in RCA connectors to the metra harness.) The orange & orange w/ black stripe are for the dimming function. (My new head unit didn’t have this, so I had nothing to connect them too. I just taped them off.)


Hope this helps anyone who might be looking to do this to their 04-05 Sport Trac Adrenalin!

One more picture correction. I had a rpm/fuel pump whine when the engine was running through the speakers and couldn't figure out where it was coming from. (yes, it literally took me 7 months to figure it out, lol)
Even ordered a new stereo as the x799 i had was used and did go through an accident in a vehicle i had previously.

Well, I finally figured out why. I was missing a ground. Pin 16 on the main stereo wiring harness wasn't grounded. It is the amp's ground. Once grounded, the engine whine went away instantly!!!!

It is the black with white stripe wire on the metra harness that needs to be grounded. (It's for the amp ground. Probably filters out any ground loop signals, i.e. removes any rpm/fuel pump whine)

2017-07-17 02.09.03.jpg

Now, I finally found another wiring diagram that showed this.
**Now while this wiring diagram is for an older explorer NOT a Sport Trac with the adrenalin stereo, it still helped me identify and confirm that specific wire, and it worked!


I decided to pull my stereo again to further clean up some of the wires.

I didn't like the rca adapters with the screw terminals. The wires kept slightly sliding out and I felt like they could touch on the rear of the connector and potentially short something out. So, instead I finally broke down and soldered actual rca leads with proper heat shrink, etc.

Cleaned up some of the wire taps too. (My cb radio is taped into the power and ground leads, as is a ground I mentioned on the previous post for the amp ground.)

Pictures are mid correcting everything.



This is the final outcome in my 04 Adrenalin


This is the final outcome in my 04 Adrenalin

View attachment 98505

I wont take delivery of my 2004 Sport Trac until early next week but according to this wiring diagram and as best I can interpret your photos, it looks like you are driving the rear speakers with RCA line level instead of amplified signals from the Head Unit. What am I missing?

@chiko I am driving ALL inputs off the RCA's. You do NOT want to drive them off the speaker outputs on the aftermarket receiver. Doing so will fry your stock Adrenalin amp. Its just like an aftermarket amp setup, you only drive an aftermarket amp with RCA's. Same goes with utilizing the stock Adrenalin amp; you just have to convert the wiring harness to RCA's when installing an aftermarket head unit. Make sure that you also get the 12v to 5v converter for the amp turn on signal. That will avoid a big "boom" or "pop" on turning on the stereo.
The last picture of the RCA's was mid process. It is just to give an idea of what was done.
Ask all the questions you need. Happy to help!

Now it is clear. My diagram is for the sub woofer amp which is what I have, not the Adrenalin. Looks like your amp also drives the rear doors, while mine uses the head unit for the rears and I have to dig into it to see if the front speakers are driven by the amp or the head unit.

@chiko gotcha. Yeah, in the Adrenalins, all speakers, front & back, & sub are driven by the amplifier. The head unit only does the processing. I am utilizing the stock Adrenalin amplifier, sub & door speakers and driving them off an aftermarket Kenwood head unit.
Good luck man!

Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!