VK Commodore Aftermarket Stereo

[MY_84_VK]

Hi, I'm new to the site, so don't really have a clue yet how to work it but I'm having a problem with my Vk Commodore Berlina.
Installed a sound system that runs a sony head deck, sony 6" and 6 x 9" and an audioline amp with a pioneer 12" sub.
The problem is every time I have the volume up loud, when I put my foot on the brake pedal the head unit cuts off momentarily then turns itself back on. I have replaced the battery and put a second hand 80amp alternator in, although I don't think the alternator is working properly, could this be the problem?
Has anyone else had this problem or does anyone know how I can fix it?
Any help would be much appreciated.
Cheers

 

[v8commy]

sounds like your head unit is powered off the brake light switch wiring and the brake lights take all the power from the head unit as electricity finds the easiest way to get to the ? i forgot that word and cant remember but u get it

 

[holdenboy]

Best thing to do is get yourself a multimeter, put the probes on the battery with the stereo cranking. If it drops below say 11v then this could be your problem......ever had a flat battery?

It also could be the constant wire from the head-unit is connected to the brake switch (as v8commy said). If you dont want to get a mulitmeter and check the battery voltage then run a dedicated power wire for the head-unit straight from the battery (fused within 30cm of the battery).

 

[MY_84_VK]

Nope never had a flat battery and I only just had a new one installed, it did it with both batteries. Think I'll try your ideas and run a wire straight from the stereo to the battery terminal and see if that fixes it.
I'm hoping it does as I'm looking to run an additional two 10" subs either side of my 12", facing inwards to really pump up the bass!
And I totally agree with 150db in a commodore, it's either pump it out like no tomorrow or don't have it at all!

Thanks

 

[MY_84_VK]

Wired the stereo straight to the battery worked a treat no more stereo cutting out!
Thanks for the advice guys!

 

[v8commy]

Wired the stereo straight to the battery worked a treat no more stereo cutting out!
Thanks for the advice guys!

are you running a fuse if not take out that wiring and wire it to the pink ignition wire on your ignition switch so take the cover from around the steering wheel and theres an ignition switch on the columm youll see a pink wire get a stanley knife cut a section of the insulator off and rapp your stereo wire around it tape it up id also run an inline fuse and itll be better as your ignition will turn your stereo off aswell

 

[holdenboy]

He's talking about the constant (yellow) wire, not the accessories wire. The standard stereo wiring has an ignition wire.
Also its not good practice to just "twist and tape", i certainly wouldnt be advising people to do it. Much better off to solder the connection and then use tape to insulate it.

 

[MY_84_VK]

Lol, yeah much better to solder it but when i make connections i split the wires connecting them twice then wrapping them two wires together, makes a nice strong hold :thumbsup:. But yes I made sure I put an inline fuse don't want the deck screwing up all together although that would be a good excuse to buy myself a new head unit with two RCA outputs and more sound options