Online Car Stereo Trouble shooting & repair service.

Owner Operated with over 35 years Car Stereo Experience.

The following is a list of car audio questions that we get asked all the time.

You may be able to fix car audio problems with this advice.

If you can not find the answer here, then Email for Mobile Car Stereo Enquiries.

Our repair service is available New Zealand wide.

If you courier direct to us we will check, Quote and repair, then courier back to you.

Nearly all car audio systems (head units) available today are Euro din size and can be installed into most modern cars, replacing the existing (din) factory system and using existing mounting brackets or the din sized mounting sleeve. Filler custom pockets are also available from us if required for filling that double sized hole.
Custom replacement dash fascia and fitting kits are also available for almost all vehicles. Email for Mobile Car Stereo Enquiries.

Some people will be able to attempt a full install. This should only be done with the knowledge that all manufactures warranties may be voided if a mistake is made in the installation process, just one wrong wire connection can mean a non warranty repair bill, even for your brand new out of the box car stereo system. The vehicle electronics may also be damaged.

We recommend you call our professionals for advice. Not only will you save time, but you can also save money. Custom brackets and plug to plug wiring looms to suit most vehicles are available from us.

All vehicle manufactures unfortunately use different colour coded wiring and different configuration loom connector plugs. This can even vary from model to model even within the same make of vehicle. Don’t guess at these, see “doing it yourself”, and seek professional advice. Custom converter plug to plug wiring looms are available from us for plug and play solutions.
Iso standard colour codes for stereo units are as follows,

GREEN = Left rear speaker positive.
GREEN / BLACK = Left rear speaker negitive.
PURPLE = Right rear speaker positive.
PURPLE / BLACK = Right rear speaker negitive.
GREY = Right front speaker positive.
GREY / BLACK = Right front speaker negitive.
WHITE = Left front speaker positive.
WHITE / BLACK = left front speaker negitive.
RED = ACC power 12volt (switchable).
YELLOW = Battery back up power 12volt (permanent).
BLUE = 12volt out to switch antenna or amp on.

Most original fitment speakers are compatible with new stereos. (Apart from some Bose systems), Speakers are of four ohm impedance (industry standard) but may be under rated in power handling. Connect them and listen, if you like the sound at your usual listening levels, you will save time and money, so do not need to replace them. If the sound is lacking, check the wiring for faults or upgrade speakers as necessary.

Please note that buying 200Watt speakers WILL NOT give you a more powerful system. The power is governed by the stereo output, not by the speaker rating. Replacements can be done at any time, if and when the budget allows.

Tip: Be wary of new speaker depth when installing in doors (your window has to fit in there as well)

Speakers all need to push air at the same time, if one pushes and one pulls, then the bass is sucked away. (out of phase) Speaker terminals have + and — (positive and negative) and must be connected similarly to the stereo amp or head unit, + to + and – to –. (similar to battery terminals). To test speaker phase.

Turn the balance from center to right speaker then through center to left. If the base disappears in center position, then reverse + and – on one only speaker. So both speakers now push at the same time.

*Check car fuses and fuses behind stereo. All modern systems require two. (One to retain memory of stations and settings, and one to turn the unit off when vehicle is not in use.)
*Is the stereo coded? Re-enter the correct code.
*Check speaker wiring for short circuits and shorts to earth on speaker terminals. (Terminals must not touch any metal parts on the vehicle!)
*Use the reset button

*Still dead? Send it to us for repair.

Re-enter known code. If code is not known don’t guess it! It can permanently lock up the stereo and make it non repairable. If the code is not known and you have proof of ownership we can decode or re code most units for you!

Send it to us for repair.

Push the reset button on the fascia of stereo and also the changer, or unplug the unit and then reconnect after 60 seconds.
Sometimes holding the Eject button for 5 seconds can work also.

No luck? Send it to us for repair.

6 Disc players can only be effectively repaired by an experienced technician. They are very complicated and there are no shortcuts. Stand alone changers and 6 Disc in dash units must be sent to us for repair, as replacing the unit can cost hundreds if not thousands of dollars.

We have adaptors available to suit ALL STEREO SYSTEMS. Some have direct input into a rear AUX input or use the CD Changer input, others are connected directly through the aerial input lead.  (These are not prone to interference as some other FM Modulated transmitters are.)

Bluetooth AUX adaptors are a great add on that provide wireless music streaming from your phone to your existing stereo and can be fitted to most existing stereo systems where a replacement stereo is not an option.

Adapters are also available for the NEW iPods & iPhones (adapting 12volt charging to the newer 5volt charging systems) to allow charging while in use. These just plug onto your existing lead.

See iPhone-iPod-accessories

iPod have had 12 volt charging on all their units up untill they changed to 5 volt on their new models of iPod & iPhone.
We now have adaptors to rectify this problem.
We have a converter that plugs straight from your old lead to the bottom of your new iPod.
Problem solved!

See iPhone-iPod-accessories

The Entire face can usually be changed for a new one that fits perfectly and has a standard sized hole to suit the new standard Din stereo of your choice with the features you require. Use our search button to see what is available for your car.
Most dash kits are now available, but because they also incorporate air con controls etc as well, they may not be a cheap alternative, but in most cases it can be done.

You also have the option to have a Bluetooth AUX system fitted to any existing system at a very reasonable cost.

Email for Mobile Car Stereo Enquiries.

If you have a BMW (E46) or MINI between the years 2000 and 2007 we can re program most of these stereo’s to full NZ specifications. (Including correct number display)

All other vehicles can be converted with our quality FM Band expanders, with built in aerial amplifiers to enable the FM radio to receive all NZ stations within range.
All band expanders change the frequency received but can not change the numbers displayed.

Our recommended and newest expanders change the frequency by a factor of 10 as no expanders can change the numbers displayed on the stereo as they are factory set. So to listen to 98.2, tune to 88.2. and or 20 (85.4 is 105.4) easy. This allows all stations from 88.0 to 108.0 to be received.
Some vehicles require a booster amplifier to power the standard car aerial (giving improved reception) and these can be purchased separately or incorporated into our quality band expanders.

See car audio accessories

To comply with the new New Zealand driving and cell phone laws you must have hands free operation if you text, or make and receive calls while driving.

If your phone is “Bluetooth enabled” then a hands free kit is the answer. This enables you to receive and make calls (by the push of only one button) to any one you have stored in the phones memory. See our Bluetooth product accessories page for more info.

Upgrading your car stereo system is also an option. See “Bluetooth enabled car audio” options on our products page.

Upgrade your stereo and have the best of both worlds with better stereo sound, and hands free for phone calls heard through your stereo system while wirelessly connected to your phone. This also means music stored on your device can be played through the stereo as well via wireless music streaming.

A small recessed switch usually located on the front panel of the stereo (the size of a pin head) so very hard to see. This button re sets the stereo’s brain to factory settings.
Use a paper clip or ball point pen to gently press.

If no re set button is obvious then disconnecting the battery for five minutes can also sometimes work. Be sure to do this with the ignition key removed while disconecting AND reconnecting of battery terminals. Also note if the stereo is coded, because you will need the correct code to be entered after re connection.

(Usually caused by bad solder joints or blown dial bulbs).
It could also be a broken flexible circuit board on flip face stereos.

After trying reset and checking fuses Send it to us for repair.

Check the balance and fader controls (reset them to the center position). Is it one or all speakers?
Check the wiring for breaks and short circuits, or bare wiring touching the metal of the car.
Call our radio technician to test the system, or replace any faulty speakers.

With possible internal component failure.

Send it to us for repair.

Check the aerial (is it fully extended?) is the lead broken or disconnected from the stereo? Check the aerial amp wire (for windscreen and stubby roof aerials) is it connected and has a 12 volt feed. All OK? Then there is a possible internal tuner fault or the wrong band expander for the vehicle has been fitted?

Some vehicles require a power lead to power up an internal aerial amplifier. Is that connected?

Call us or Send to us for repair.

If the reception is OK on AM then send to us for repair as it is usually an internal tuner fault.
If there is no AM reception as well, check the connections, is the aerial plugged in? See notes above.

Send it to us for repair.

Call Auckland Mobile Car Stereo, Ph: 021-935-374 or 09-444-5883 for Mobile on site service, and help with stereo removal from your vehicle. This can be done at your home or work within the Auckland metro area.


If outside this area, have it removed (possibly by your local Auto Electrician or Mechanic) and INSIST it be delivered to us by courier, as we have the fastest turn around time and best repair service available in New Zealand!print a repair slip, and send for repair

Usually repaired and returned within 48 Hrs.

Get the Car stereo removed and couriered directly to us from anywhere within NZ (the cost is usually less than $10.00)


If the unit accepts CD momentarily and then ejects, then the problem is usually in the laser lens, being dirty or too weak and unable to read CD information.
If you can not hear CD spinning then it is possible that the motor is faulty.

Try the reset switch, and if no luck, Send it to us for repair.

Leave the tape or CD in place and send it to us for repair. Do not try to remove.
To force tape or CD removal can more than double the repair cost (replacing broken or bent mechanism parts as well as removing the jammed tape or cd)

Send it to us for repair.

Seek professional help on this. Specialist knowledge and tooling is essential.
In some instances metal cut from a vehicle can alter the strength, and therefore the safety of that vehicle. Enlarging a cavity to accommodate an oversized speaker may render your vehicle unsafe and therefore un warrantable. (no warrant, no insurance, and also not legal to drive on the road).

Automatic aerials can usually have the broken “mast only” replaced (no need to replace the motor as well). The mast only option is very cost effective, sometimes being less than 1/4 of the cost of a total aerial replacement.

We also have electronic stealth aerials that adhere to the vehicle windscreen and therefore not broken again.

Contact us. Email

For custom manual aerials, & after market aerials, buy cheaper through this site than through a car dealer (genuine?) parts department.

Help with fitting can also be provided.

There are a limited number of 24volt stereo units made.
I suggest a 24 to 12 volt converter that will enable you to add any standard 12 volt stereo to a 24 volt system.
Be sure to get one that has two inputs and two outputs (for back up and switched power) and can handle the power draw. Enquire at

Many people don’t know what quantifies a good sound system. Audiophiles generally refer to the following qualities in determining how good a sound system is: Imaging, staging, dynamics, and spectral balance.
Spectral-balance is most important. This is the sound system’s ability to play evenly across the entire audible spectrum, which is usually defined as 20hz to 20khz (20 vibrations/second to 20,000 vibrations per second).To achieve an even balance across this frequency range a good system will use specialized speakers to cover various parts of the frequency range:

Subwoofers handle the lowest bass (20hz-80hz), woofers would handle the bass chores, midranges would handle the frequencies above that, and tweeters are sent frequencies in the highest ranges (about 5khz and above).

In a standard car audio system, you will usually find a single speaker trying to handle the entire frequency range by itself (although sometimes it’s broken into a 2-way design, with a tweeter sitting on top of the main speaker). The reason that this doesn’t work well is that the physical properties that make a speaker good at a certain frequency range make it bad in another frequency range. For instance, a subwoofer is good at moving very large volumes of air with it’s large cone area and heavy mass. But that heavy mass prevents it from moving quickly enough to handle the high end frequencies.Additionally, cars introduce alot of noise to the equation, and most of this noise is in the lower frequencies. Because of this, the audio system has to play a lot louder in those frequencies to compensate for the noise floor as it is called. If the noise generated by driving is equal to 48db, then the speaker producing sound in those frequencies has to be 48db louder than the rest of the audio system to compensate for it. 48db translates to 32 times more power needed!So, placing a high-power subwoofer into the system allows it to handle these demands.

After that long-winded explanation, it all boils down to this question:

Is it all worth the trouble? That depends on you the listener. The best way to make this decision is to listen to some music on a standard system, then listen to one with a subwoofer. What you’ll likely hear (depending on the source music being played), is that there are bass lines in the music that the standard system isn’t playing that you are not able to hear. With some music it is obviously more pronounced than others, but not necessarily as you would think. For instance, Enya CDs are often thought of as light music, whereas rap CDs are thought of as bass-heavy. But Enya’s biggest hit CD Sheppard’s Moon has a lot more low frequency material than the majority of rap albums. Most people wouldn’t know that unless they listened to it on a quality sound system with a good subwoofer. So, after listening to the good system did you notice the difference? (Some people’s hearing is not good enough to hear the extremes of the frequency range, particularly as you age) Was the difference important enough for you to want to spend money on a subwoofer?

Sometimes just adjusting the tone controls to what you like in music is a good step and all the improvement needed. Hope that helps