Maybe fuse blown? Need electrical help!

[Sotovo]

About 4 months ago, I had Best Buy install an aftermarket Kenwood radio head-unit. Nothing else, just the head unit to start.

1 week ago, I got back in my truck and started it like usual. Of course when I started it up, the radio came on because I was listening to it before I had reached my desitination.

When the radio came on, it started making this lower sounding rumbling, and then revved up into a high pitched whine and whistling sound. And just it just stayed there. Very annoying noise. The head unit was frozen screen and wouldn't respond to any volume change or power button pushing. So I disconnected the radio unit and it STILL kept making the noise. I had to drive all the way home. It was so annoying! Finally I got home, and started trouble shooting. I tried everything. Taking the unit off and putting it back on, restarted the car multiple times and even hit he little reset button behind where the unit sits. Nothing worked, so I finally I decided to try and disconnect the battery, I did and then started the car back up. The noise was gone, but now the radio head unit seems to not be receiving power at all. It's like pressing buttons on a brick. Nothing.

To make things weirder, my alternator completely died 2 days later. (took it out and had it tested, it scored a 0 function for the test) so I thought maybe that had something to do with it not receiving power. I replaced alternator and nothing had changed.

Thoughts? Maybe it's a fuse? I can't find my warranty info so I'm hoping this is just a fuse or something simple. Help!

 

[Toyotayoda]

Your alternator kicked it, radio was acting weird and buzzing because of it's lack of voltage. The alternator receives it's voltage via that 8 gauge cable with a 80-120 amp fuse in the PDC under the hood, if thats blown it's been working overtime for some reason. Nobody for any reason should have messed with any of the wires going to the alternator, they are too far away from the radio, and don't supply the nice clean DC you want for a radio.

Also if you didn't fully charge your battery before starting your T4R, you could have killed your new alternator, they are only designed to keep a battery charged not charge a depleted battery.

 

[Sotovo]

Your alternator kicked it, radio was acting weird and buzzing because of it's lack of voltage. The alternator receives it's voltage via that 8 gauge cable with a 80-120 amp fuse in the PDC under the hood, if thats blown it's been working overtime for some reason. Nobody for any reason should have messed with any of the wires going to the alternator, they are too far away from the radio, and don't supply the nice clean DC you want for a radio.

Also if you didn't fully charge your battery before starting your T4R, you could have killed your new alternator, they are only designed to keep a battery charged not charge a depleted battery.

It is a new battery, so no worries there. Also, I started it with a jump start and allowed the vehicles to stay connected and charge for a while. So we're all good.

As for you addressing the electrical issues, I'm really only seeing you stating has has happened. Could you please provide some direction on what to do? Thanks for the knowledge friend.

 

[wcjeep]

Some stereos require a code to restart . If battery voltage is lost the code would be necessary. The battery should have been fully charged before installing the new alternator. Most alternators do not have a 100% duty cycle. It's possible your old alternator damaged the stereo.

 

[TheDurk]

Some stereos require a code to restart . If battery voltage is lost the code would be necessary. The battery should have been fully charged before installing the new alternator. Most alternators do not have a 100% duty cycle. It's possible your old alternator damaged the stereo.

A codeless HU is not totally dead like his.

I'd say it is time to go to square 1. Check voltage at battery with engine running (13.5-14.5) and with key off, after ten seconds of high beams (should be 12.5 V or better.) Check both power feeds to radio--usually a yellow and a red. with a test light or meter. One is full-time, the other is key on. If both are good, check radio for fuses on the outside. If none, see your manual, they may be internal. If no fuses in radio and both feeds are good, it's toast.

If a feed is bad, then you need to check its fuses up the chain all the way to the battery. Do NOT just LOOK at a fuse, use a test light, a meter, or swap in a known good fuse. Stock power feed is the DOME fuse for full-time and ACC for key on, but either or both may have been modified when an aftermarket HU is installed. Look for an inline fuse in any yellow or red wires going to the radio.