Car startup issue - electrical over-loaded at start from sound system?

[ZaneNBK]

I recently had a sub w/ 450W amp and another 4x50W amp installed along with a USB power adapter. When I start the car with the phone plugged in, my steering wheel controls (connected through an adapter to an aftermarket head unit) don't work properly about 90% of the time. If I connect my phone after the car is started the steering wheel controls always work fine.

The phone is connected to the USB power adapter that's wired up to the head unit's wiring harness where the steering wheel adapter also draws power. I'm guessing the system is overloaded when the phone is plugged in and drawing just a little extra juice which is causing the steering wheel adapter to be under-volted and it starts up improperly.

Any thoughts or suggestions on fixing this? Currently I just plug in my phone after the car starts but I'd rather resolve the issue.

 

[DominionSeraph]

Take it back to the shop that did it.

 

[JCH13]

Agree with taking it back to the shop that did it.

There might be some fail-safe measure that's disabling the controls if it detects an under-volt condition. Something similar happened in my fiance's old Accord.

 

[ZaneNBK]

Agree with taking it back to the shop that did it.

There might be some fail-safe measure that's disabling the controls if it detects an under-volt condition. Something similar happened in my fiance's old Accord.

That's not what's happening though. The steering wheel controls (volume/mode/etc...) are still working, just not correctly. For example the forward seek button does volume down instead of the proper function when I start up with the phone connected to the USB power adapter. (again, about 90% of the time)

I could take it back but I did the original head unit install and installed the steering wheel control adapter. The shop just added the USB power adapter, amps and speakers.

 

[xanis]

I don't know much about this stuff, but maybe the new stuff is drawing too much power when you turn the key and you need a better battery?