Troubleshooting power issues to head unit
 

Hey, new to the forum and I've found it very informative so far.

Recently got an 84' Blazer S10 in pretty good shape, but the head unit wasn't Bluetooth so I wanted to upgrade. The old head unit was having power issues, cutting out and restarting intermittently and eventually every five seconds.

I installed a new JVC unit myself and everything went well with the wiring. It started playing music fine, but then it turned off and restarted when the music got loud. I turned the volume down, but could see the lights on the head unit flickering when the bass hit. I turned on a podcast quietly and it didn't lose power.

Any ideas? I'm pretty new with car electronics/audio, but I'm thinking of checking the fuses then maybe replacing the big three wires. I don't think it's an alternator issues because the same thing happens whether running off just battery or with the engine on.

Thanks very much for any help,
Evan
https://cimg2.ibsrv.net/gimg/blazerf...a748e39950.jpg

Sounds like it's a power issue. If the lights are flickering when the bass hits, it means the amplifier is trying to draw more power than your truck can supply.

Do you have a sub & amp setup, or just the head unit and regular speakers? If no amp and sub, then the problem is most likely with the dash wiring to the head unit and the first thing I'd look at is upgrading the ground. Your ground should go to a bare-metal ground on the body, not just a brace in the dash. If that doesn't fix it then you can upgrade to a dedicated fused power wire to the head-unit. You probably don't need to upgrade the switched power wire, as the head unit doesn't draw power from that source.

You may also want to consider doing the big 3 power wire upgrade under the hood (search on the forum for details if you don't know what that is) if you have a sub and amp.