We will explain what to do if there is no antenna wire in the car harness below.
Driving is more fun when you have good music flowing through the speakers. And the only way to get the music from the car speakers is via the stereo head unit.
If you opt to listen to the radio, you will need an external antenna to get the best reception. But what if your car’s radio wire harness has no antenna wire? Here’s how to work around this issue.
Table of Contents
- What Is a Car Radio Harness?
- Replacing a Stock Stereo
- Test and Mount the Aftermarket Head Unit
- Wrap Up
What Is a Car Radio Harness?
This wire harness is the cable set or bundle that powers a car stereo and its connected components, including speakers, amplifiers, reverse cameras, and antennas.
Replacing a head unit can be challenging because each of these wires has a color code to indicate its function. And since we are interested in the antenna, the color code for this component is a blue wire.
An aftermarket single-din car head unit
Don’t confuse this wire with the one that has a white stripe. The blue/white wire is an amp wire that tells the external amplifier the head unit is on, so it should turn on. It passes this message by triggering the amplifier to turn on.
Replacing a Stock Stereo
The first step in improving your sound system is to replace the factory radio. You will need your vehicle’s schematic to identify the screw and clip locations to loosen the unit from the dash. But first, remove the dash trim covering these screws.
Once you remove the radio, disconnect its wiring harness and pull the blue power antenna power wire from the back of the unit.
A car stereo wiring harness
If this factory wiring harness has a powered radio antenna, this wire might have the label “PWRD ANT” or “ANT.” Match this wire with the antenna wire in the aftermarket radio harness.
But if the aftermarket head unit has the blue lead for the powered antenna, and the factory harness lacks it, crimp the wire using an insulated connector over the bare wire. Don’t connect it to any part of the system.
It is vital to note that some new aftermarket head units don’t come with a separate power antenna wire. They only have the antenna trigger cable (blue wire with a white stripe), which you can use to power the antenna.
The only downside is this cable keeps the antenna out when the head unit is on because it keeps the 12V power supply on throughout.
Blue antenna wires in factory radios retract or lower the antenna when you exit the AM/FM source to the others, such as USB or AUX, because they cut the power supply. But this is a non-issue if your vehicle does not have a retractable antenna.
A retractable car radio AM/FM antenna
Will the Radio Work With No Antenna Wire in the Factory Harness?
Yes, it will. The antenna wire only helps improve reception in fringe areas. But the radio will receive stations if you are close to the transmitter, such as in urban areas with few skyscrapers.
However, we recommend using antennas because they enable your stereo to receive and pick up stations with transmitters up to 50 miles away.
Also, you don’t need an antenna if you don’t plan on using the AM/FM radio source. Streaming from AUX, Bluetooth, and USB is even better because these sources give better audio quality.
A double din head unit with multiple sources, including USB
But in some cases, the radio might not work. It might even fail to turn on. If such a head unit has a passive antenna power, it might use the blue wire to strengthen the grounding to the vehicle’s body.
Therefore, if the aftermarket stereo has an antenna wire, connect it to the blue or blue/white wire in the factory harness, even if you don’t plan on using the radio. Avoid shaving the antenna or its wire.
But it is worth noting that radios conventionally ground their systems through the black ground wire. So, if you don’t wire this cable correctly, the aftermarket head unit will find its ground through the antenna.
If this connection is also absent, the stereo will not work because there won’t be a low voltage potential connection to allow the current to flow.
Test and Mount the Aftermarket Head Unit
Reconnect the antenna cable and all the other wires in the harness using the wiring guide in the new stereo. You can use a color-coded aftermarket wire harness adapter to simplify the process.
A car audio player connecting cable adapter (note the color codes)
After that, test the unit and check all its functions, including AM/FM, reverse camera, and other sources like USB, dimming, etc. If everything works, insert the system back into the car.
Remember to tie the wires using three or four zip ties to bundle the individual cables to make them neat.
Slide the wires and the head unit back into the dash, then fasten the stereo using the screws you removed earlier.
Lastly, insert the dash trim to cover the screws. If the head unit is broader than the trim slot, install a new one to leave the entire screen out.
A double-din head unit
Do a last check. Try to tune in to different FM radio stations and listen to the sound output from all speakers. Adjust the equalizer (fade, balance, etc.) until you get the desired sound output quality.
Wrap Up
Antenna wires are vital in a car head unit harness, but you can do without them if you don’t intend to use the AM/FM source for entertainment.
However, you have to connect the black ground wire properly to keep the radio from trying to use the antenna ground.
When doing the antenna wiring, you can use the blue or blue/white wire, depending on the available one. Either can work, but always use the former if available.
That’s it for this article. Check out these car-stereo wire harness color codes to help you complete the stock head-unit replacement process.
