


🔧 Upgrade your ride’s sound system without the drama—Metra makes it effortless!
The Metra 70-5521 Radio Wiring Harness is a precision-engineered solution for integrating aftermarket radios with factory amplifiers in 2003-2005 Ford, Lincoln, and Mercury vehicles. Featuring plug-and-play connectors, dual RCA pre-amp outputs, and a built-in resistor to eliminate turn-on noise, this harness ensures a clean, professional installation that preserves steering wheel controls and factory wiring integrity.


| ASIN | B000K50GTA |
| Best Sellers Rank | #77 in Car Audio & Video Wiring Harnesses |
| Brand | Metra |
| Connector Type | RCA |
| Customer Reviews | 4.4 4.4 out of 5 stars (3,837) |
| Date First Available | October 28, 2006 |
| Global Trade Identification Number | 00086429129522 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 0.32 ounces |
| Item dimensions L x W x H | 0.02 x 0.02 x 0.02 inches |
| Item model number | 70-5521 |
| Manufacturer | METRA Ltd. |
| Material | Copper, TPU |
| Product Dimensions | 0.02 x 0.02 x 0.02 inches |
| UPC | 086429129522 |
| Warranty | Please contact the manufacturer |
| Weight | 0.2 Pounds |
J**F
Does the job, I was just unclear as to wether I needed the amp out plug
Just bought a ‘04 Lincoln Town Car and didn’t know wether it had an amp/sub or not(couldn’t speak with original owner as it was purchased through a family member and the manual was missing) so I went with this harness because if I didn’t need the amp out harness no big deal, but if I did...well then I’d need it lol. The harness itself is perfect for what it is, a simple harness to prevent cutting and splicing the OEM harness, wires were clearly marked and colors matched the harness for the after market stereo. Went with the Pioneer AVH-X490BS, if you get a pioneer look into getting the parking brake bypass switch. The only problem is that there was nowhere to connect the two blue wires on the harness with the RCA plugs, so I assumed I didn’t need it and just didn’t use it. Reconnected negative terminal on battery and tested radio and it worked great so I figured I was right. I go to install the Infinity Kappa speakers in the rear deck(btw if you have a Town Car be ready to take out the entire rear seat, both bottom and rear cushions to get access to the speakers......) and guess what I see?? A sub and amp.... I was planning on getting an amp for the speakers anyways, and maybe a 8” sub just for a little bass so I’ll just wait to get them rather than hook up the factory amp/sub. If you're replacing a radio you can’t go wrong with Metra, always quality products. Been using them as long as I can remember, and between work, my personal vehicles and friends/family I’ve installed more car stereos and speakers than I can remember and never had an issue with Metra.
V**A
Steering wheel function, no need to buy extra harness
I used this harness to upgrade to an aftermarket head unit on my 2005 f250 6.0. Worked flawlessly. My new headunit did not come with steering wheel control functions and says you have to buy the harness for it seperately. You do not. Its a very simple process to retain your functions that i learned about way later. Your upgraded headunit will have a harness included. On that harness it will have a wire labeled "Steering wheel key (+)" and it is orange with a black stripe (atleast on mine) Your stock truck harness will have a blue/red stripe wire on Pin #18 that you must tap into. You dont have to cut it, you can simply military splice it, or use a T-tap to connect the SWK wire on your aftermarket radio harness to connect to your factory harness. Once you connect this SWC(+) wire onto the blue/red wire.. you will be able to setup your functions on your radio. Thats it. One wire. No need to buy the access module or the maestro kit thats around 100 if you have a powerstroke. Hope this helps someone.
M**A
Great fit for 2008 Hyundai Sonata
Even thought this is labeled for Ford, this was a perfect fit for my 2008 Hyundai Sonata. This item comes with two adapters, I did not need to use the harness with the smaller adapter, I believe this might be to connect an amp which I did not need. I was struggling to find the correct adapter for the 2008 Hyundai Sonata because searching on amazon and google were not leading me to this adapter from Metra since it is labeled for Ford. I came across a youtube video with a guy working on the Hyundai Sonata 2008 and he was using this specific cable model Metra 70-5521 on his stereo. So I decided to order it after searching it up and comparing the adapter to the car's factory adapter. It worked out great because it was a perfect fit. I youtubed enough about the basics of wiring cables together, what the different colors mean, pros and cons of wiring directly to the factory unit wiring (using no adapter). I found videos of others removing the stereo for my specific car (I didnt want to just pry it apart and damage something). Then I went the method of butt connectors to link the wires from this harness to the cables of the stereo unit. The connection quality is strong, the cables from this harness are sturdy so they link well. I used it to adapt an aftermarket radio (BOSS Audio Systems 616UAB single din) using the car's existing factory wiring and connectors. I got the single din install kit (Metra 99-7320). I also got the LeeKooLuu Backup Camera and wired it to the Reverse tail light. I installed this for my girlfriend and it passed her approval test. Everything came together perfectly.
A**A
Works well, BUT
I used this in an '06 Mustang GT. It was easy to wire up, everything was labeled nicely and wiring is good quality. If you have an amp, there are a couple extra items you may need. First is a 12v to 5v voltage converter, this just gets tied into the amp out (blue/white), otherwise you may get popping sounds with On/Off. The second in my case, I needed to add a line out converter from the RCA. This allows me to adjust the gain. Initially I wired this up without it and the sound was terrible, way too much volume sound coming from the amped speakers. I emailed their tech support a few times, they were helpful but ultimately the manufacturer of the head unit I bought recommended the solution. Otherwise it works as intended.
R**T
Great product, as described. Made installation a breeze
If you’re using this, look into other accessories to retain steering wheel control too. Draw a wiring diagram. Make sure you have everything you need. It works perfectly. Used it to install KENWOOD DDX9707s on a 2010 Lincoln Towncar. Glad I bought it. Make sure you buy butt connectors to connect the harness with your radio/steering wheel control
E**.
El arnes quedó a la perfección, muchas gracias solo que al querer conectar el arnes chico mi camioneta ya no trae el conector macho que es para el subwoofer de fabrica que trae la camioneta la cual es una explorer eddie bauwer 2005.
E**P
This just arrived after waiting patiently for its arrival from the USA. Unfortunately this does not fit the Ford Explorer 05 as stated. Good quality item, but clearly a waste of time and money as seller is USA based, this isn't worth a return!
R**N
I used this to install an aftermarket stereo in our 2010 F150 with no Sync. I searched many places and couldn't locate the correct harness for my truck. I could tell physically this would fit so I used it, however I know it's not intended for my truck. That said all speaker connections were perfect, yellow memory and ground matched, only the illumination wire didn't match so I moved that pin. Great quality and worked well.
D**A
TODOS los productos Metra que he comprado a traves de los años han sido extremadamente precisos, me ayudan a presentar un trabajo super profesional, mejoran enormemente el "look" de mis automoviles, y me facilitan la instalacion de los nuevos estereos. Siempre que pienso en un estereo nuevo para mi auto, lo primero es encontrar el producto Metra adecuado al vehiculo, y siempre lo hay.
J**N
Fits Perfectly and works as it should, good plug ... Fits Perfectly and works as it should, good plug ... Fits Perfectly and works as it should, good plug ...
Trustpilot
2 weeks ago
5 days ago