Potential Alternator/Voltage Issues

I'm having weird issues.. The other day my car started making a fan whirling noise, which I believe was the alternator... it went away.. but then the next day my radio would shut off when I engaged the brakes... This all started when I bought a new electric cooler for car camping... and testing it out with the 12v normal charger...

I have a thought that maybe my battery is getting drained from something when it is off...
Maybe this connected to the battery? ... I'm assuming it's something to do with a head unit or something similar.. I think this could be a factor.

 

Previous owner probably had a system. You will have to follow the wiring.

 

Thanks! I've been having weird issues that I thought was alternator related, like when I engage my brakes, my radio shuts off... I just got an electric cooler for car camping, and I believe it has exposed this issue.. The alternator seems to be charging the battery, but potentially something is draining it when the car is off.

 

Looks to be a fuse.

Follow the wire and figure out where it leads... Alternatively you could disconnect it and see what happens lol. Might just solve your voltage issue...

 

Thanks. I don't know how to test it really.. I don't have a voltage reader, and not very knowledgable with wiring... I'm trying to eliminate the possibility of an alternator issue. Your suggestion makes sense.. lowest hanging fruit.

 

My bet would be its power to a head unit or amp somewhere in the rig. If it was my rig I would chase the wire first and see where it leads. If you can't find where it goes you could

1: Check the voltage with vehicle turned off. Should be around 12.5v
2: Check the voltage when the vehicle is in accessories on. Should be around 12.5v
3: Check the voltage at idle. Should be around 13-14v

Disconnect that wire and do this again. See if your results change.
Also see if your stereo and all accessories and lights still work without it being connected. That should lead you in the right direction

 

Perfect! thanks for the voltage readings.. i'll have to get a multimeter.