Imagine going out with friends in your car and listening to your favorite bass track.
But the music turns off in the mid-song, right when the bass is about to drop!
Having no idea what to do, you check your car’s audio components.
And all of them are working fine – except the amp. Its power LED is off. Instead, you have a red-colored LED light turned on next to the ‘protect’ label. This LED indicates that your amp is in protect mode.
It is a safety feature that protects the amp against fatal damage by shutting it off.
Usually, it happens when you have some problem with the amplifier wiring, speaker impedance, battery voltage, or in-line fuse.
These issues are pretty varied. Therefore, there’s no single way you can follow to ‘bypass’ this protection mode.
Instead, you’ll have to inspect different areas of the car audio system and identify where the problem originates.
Why is My Amp in Protect Mode?
In many cases, load mismatch is the reason behind the protect mode. The amplifier manufacturers specifically list the power output of their amps at different impedance levels, such as 6 x 125 Watts @ 4 Ohms or 6 x 200 Watts @ 2 Ohms.
So, if your speakers/subs require more power or lower impedance than the one for which the amplifier is designed, you’ll get a load mismatch.
This mismatch will cause the amplifier to overheat and go into the protect mode.
An amp can overheat even when compatible with your speakers/subs. That’s because most people put their car amps in congested locations. These locations lack proper airflow and collect dust that can seep into the amp over time.
Both of these issues cause an amp to overheat. A very common indicator of this issue is the ‘earthy’ burning smell inside your car. It’s the result of the dust accumulated inside the amp that is now burning due to overheated internal parts.
Another common reason for the amp going into protect mode is the blown speakers or subwoofer because they create a short circuit.
Too Low Voltage
If you have a heavy-duty amplifier (5 or 6-channel), your vehicle’s electrical system might not be able to handle it – more so if you haven’t upgraded the big 3 electrical wires.
In that case, you get a voltage drop, and the amplifier goes into protect mode. That’s because the car amps are designed to only work with 10-16V voltage.
A common sign of voltage drop is headlights dimming whenever the bass hits.
Too High Voltage
This situation is totally opposite of the one we discussed above.
In this case, your vehicle’s voltage regulator malfunctions and causes the voltage to go too high (16V or above). Since a car amplifier isn’t designed to handle this high voltage, it goes into protect mode to prevent fatal damage.
DIY installers often overlook labels while installing a car amplifier and connect the power wire to the ground wire terminal (and vice versa).
This reverse polarity causes the amp to go into protect mode.
If you have none of the abovementioned issues, the amp may be in protect mode due to malfunctioning internal parts.
How to Get an Amp Out of Protection Mode
Check the Voltage on the Amplifier
The first thing we’ll check is the voltage coming into the amplifier. We’ll need a digital multimeter for this process.
Set the multimeter to ‘DC Volts’ mode. And connect the positive multimeter lead to the +12V amp terminal and the negative lead to the ground terminal.
A low reading, such as 0, indicates a voltage issue with your power wire. You should physically examine this wire and confirm that it has no damage and that its connection to the positive battery terminal is solid and has no corrosion.
The other thing you should check is the in-line fuse. If it’s blown or loosely connected, you’ll not get any power from the battery.
Fix All The Cables, Connections, and fuses
The car amp can only get its required power if the wire gauge is correct and connections are secure. Therefore, physically inspect your amp cable (power wire, remote turn-on wire, and ground wire) connections at both ends and fuse holders.
If you see any loose connections, fix ’em.
The wire gauge is also crucial because it determines the current flow that can pass through that wire. That’s why you should double-check all the calculations for wire gauges you made while installing the power and ground wires.
You should also check (and fix) the speakers and subwoofer wires. If these wires are pinched, touching any metal surface, or touching each other (at the speaker or amp terminal), the amp will go into protect mode (or even blow up in some rare cases).
Lastly, we’ll check the amp fuses. That’s because a blown fuse can cause the amp to turn off, and you may wrongly think it’s in protect mode.
To test any fuse, you need to set the multimeter to ‘continuity’ mode and connect its leads to the opposite ends of the fuse. A beep sound will indicate that the fuse is working. Otherwise, it’s damaged, and you should replace it with a new fuse. The new fuse should have the same amperage.
Fix Overheating and Load Mismatch
An amp can overheat either due to ventilation or load mismatch. That’s why we’ll check for both of these issues here.
If the amp is overheating mainly due to poor location, that’s easy to resolve. You’ll have to relocate it to an open/airy and clean space inside your vehicle and install an amplifier fan if necessary.
On the other hand, if the overheating is due to a load mismatch, then resolving it would be lengthy.
That’s because you’ll have to double-check the calculations you made while setting the impedance for the subwoofer(s) and amplifier.
Disconnect The speaker
Now that we’ve checked the amplifier, it’s time to check for the speaker. You can do this by disconnecting the speaker wires. If it makes the protect LED turn off, then the speaker likely has been damaged and will need to be replaced.
Check Head Unit Wiring
This issue is more common in aftermarket head units. That’s because we unintentionally make loose wiring connections while installing the head unit, which creates problems for us down the road.
If the remote turn-on wire is not connected to the head unit harness or isn’t correctly matched, the amplifier will go into the protect mode. So go through your harness wiring diagram and physically check the back end of your head unit to ensure that’s not the case.
Check Your Ground Connection
Many times a bad ground connection will cause an amp to go into protect mode. So check the grounding spot and ensure it’s a proper metal surface with no paint/corrosion. You can read our blog post about car amp grounding for more information.
Check Battery Voltage
Checking the battery voltage is similar to how we measured the voltage at amp terminals.
But instead of amp terminals, we’ll connect the positive multimeter lead to the positive battery terminal and the negative lead to the negative battery terminal.
You should have a reading close to 12V. If it’s too low, there’s an issue with your battery, and you should repair/replace it as soon as possible.
So these were methods you can follow to get your amp out of the protect mode.
Yes, going through all of these steps takes a lot of work. But it’s equally crucial since the protect LED can turn on for various reasons.
If none of these worked for you, your amplifier has an internal issue. It’s equally possible that it’s dying due to aging.
It would be best to get it repaired by a certified professional or replace it with a new amplifier.
Frequently Asked Questions
How Do I Get My Amplifier Out Of Protect Mode?
You have to check and fix many issues to get the amp out of protect mode, such as amplifier overheating, too low/too high battery voltage, blown speaker, etc.
Why Does My Amp Goes Into Protection Mode When Bass Hits?
If the amp goes into protect mode only when the bass hits, it’s usually a sign of load mismatch or a low battery voltage.
Will An Amp Still Turn On With A Blown Fuse?
No, you can’t turn on a car amp with a blown fuse as the circuit is ‘open’ and the current can’t flow through it.
Can Subwoofer Cause An Amp To Goes Into Protection?
Yes, if a subwoofer is blown or is too powerful for your amplifier, it will cause the amp to go into protection mode.