Alpine ktp-445u installed in Chevy Sonic issues, advice needed

Jonnyrotton Newbie
May 21, 2019
Hello everyone, newbie, and audio idiot here. I recently purchased an Alpine power pack amp for a 2012 Chevy Sonic and wanted to leave my head unit stock and possibly the speakers stock. It was professionally installed because I don't trust myself. I'm 45 and am past the age of wanting the ultimate audio sound. So with the current set up, I am pretty satisfied with the improvement to the quality of sound the Alpine amp gives the 6 speaker stock set up.

However, there are a couple of issues I was hoping you guys with your experience and knowledge might be able to shed some light on. First off, right after the installation and checking it out with the tech, everything worked as it should, so I paid and happily drove off. After getting home and leaving to go to the grocery store is when the issues started to show up. 

The first thing that happened was returning to the car and opening the door, the dash lights and temperature control lights came on but not the radio lights, which was left on but turned off when the ignition was turned off and door opened, like it always does. Well I turned the radio on at the head unit and the back lighting on the display was in night mode, so dim lighting, and it was still daylight considering it was around 3 pm. Then I noticed that the steering wheel volume and station controls would not work. I immediately called the installer and explained what was going on and he said when he gets a chance, he'll have to look at it but it might be awhile because he's very busy for the next couple of weeks.

Now the steering wheel controls will start working again after the radio or car has been shut off for awhile. But when the steering wheel controls are not working the radio will not shut off when the key is removed and the door opened like it's supposed to. But if the steering wheel controls are working it shuts off when key is removed and door is open like it always has before the install. The radio can be turned on without the key, regardless of whether the steering wheel controls are working or not, which doesn't bother me much. I just want to to automatically turn off with the key out and door open.

The second thing I have noticed, is the amp will get hot if the music is played fairly loud, not crazy loud. I actually measured it at 130° with a laser thermometer. And I have read on other forums that it only gets warm to the touch when pushed hard.

I mentioned these things to the installer, and his thoughts were the way I requested it be hooked up was probably the reason. I bought the male and female connectors with the power and speaker wires so the amp could be installed without cutting it splicing the factory wires. I mentioned that the instructions said as long as the head unit is on a 15amp fuse, that the Alpine amp could get it's power from the stock head units power. And told him I'd prefer him to hook into the stock head units wires for the power.

His response was, he thinks the amp is not getting sufficient power because the stock head unit wiring isn't providing it with enough juice making it work harder, heating it up. And because my Sonic supposedly has a "canbus" electrical set up, that it could be when the amp starts trying to pull more power than should be permitted through the head units power wires that, that is when the steering wheel controls stop working.

I asked, if the amp isn't getting enough juice, why is it getting so hot? Doesn't it require a good amount of power to get hot? So if it has enough power to get hot, shouldn't it operate just fine?

So, as you can see, complicated, and I have no experience or understanding of electrical mystery.

Any ideas what is causing the steering wheel control issues and if the Alpine should or does get that hot normally? 

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