@Yosemite I considered that possibility, but if that were the case wouldn’t the stereo continue operating even when the ignition was off?
@“MY 2 CENTS” Time to dead varies, this time of year it’s not always possible to drive a Miata in Colorado so it can sit for a few days or a week at times.
@“Honda Blackbird” I don’t doubt you but if this is as common as you say I might just put back the original factory stereo and forget about it.
The best thing to do is check the current draw to see how many Milliamps are being drawn.
Some more info might help.
Did the problem only surface after the stereo install?
Who did the install?
Does the car have an amplifier?
Have a power antenna?
Nooo no no…I’m sorry…I only see this issue as “Semi Common” because I was exposed to literally 1000’s of Radio systems and among them I saw this happen maybe 5X at work… Make that 7X if I include YOU and my Girlfriends 96’ Mustang GT with the old Factory Radio…this is over the course of about 18yrs… So please don’t even think/worry about this issue its not prevalent enough to worry bout, seriously. Just replace the radio and move on… The likelihood of you seeing this issue again is Very VERY SLIM my friend…Honestly don’t even worry about this anymore and enjoy some tunes. Totally SILLY to worry about this happening in the new radio you buy.
Blackbird
I’ll bet lunch that when you pull that aftermarket unit out you find that it’s been “hard wired” in… butchering the OEM harness. If that’s the case, and you follow the same wiring practice installing the new unit, you may still have the problem. The solution if my guess is right is to reconfigure the OEM harness with a proper connector, then use an adapter plug to install the new unit. You may want to have a shop that specializes in automotive electrical systems do this… NOT a shop that specializes in audio systems. They’re not the same thing.
Shame I cant take a look…I’ve had to repair so many “Hack” jobs behind peoples dash boards… Its easy to correct when you pull the wiring diagram and just take it slow. I bet Mtn Bike is correct…Someone could have very easily decided to skip the 15 dollar conversion plug and wire it up on their own… and thus TOTALLY screwing things up when it could’ve been so easy. Perhaps they wired the radio to the constant 12VDC wire that is used for memory and clock functions…instead of the “switched” 12VDC wire. This stuff isnt rocket science…but some people think their abilities are FAR greater than they actually are…and have to be heros. LOL This isnt a difficult issue to resolve…
Blackbird
A few people have suggested that the wiring is wrong, so that the wire that should be switched is actually getting full time power. But wouldn’t that mean that the stereo wouldn’t turn off when the car is off? It does turn on and off with ignition, which sure sounds like it’s at least wired correctly.
@ok4450 it’s hard to be sure if the problem started with the stereo install. The previous battery lasted only 3 years-- maybe the stereo was responsible, maybe not. It was installed at Car Toys, and there’s no amplifier. There is a power antenna.
3 years is not a problem. Get a new stereo head and the required wiring harness for your car. You should be good to go.
@atomicbird, you are just not understanding it. That aftermarket stereo is malfunctioning electronically. It may just be behaving normally, but there is a module still drawing power instead of going to sleep. Which one, who cares? Maybe the power amp module, or the CD drive module. It doesn’t matter. It would cost you much more money to find the fault than to just replace the entire unit unless the one you have is under warranty. If you still have a functioning factory radio, put it in and see if it fixes your problem. I’ll bet it does.
Maybe a higher cca or new battery is the solution.
Wonder if there’s any chance that the stereo wiring could be tied into a circuit which is possibly energizing a relay or what have you and in turn, activating something else.
Stereo installed with a stereo car specific installation kit or with a handful of Scotch-Locks and a test light probe?
My 2006 Ford Focus stock radio was drawing .86 amps, I found the fuse and pulled it, now there is only a .04 amp draw so the radio was it, is there any way to salvage the radio or is it just time to replace it?
Under what conditions? Radio on/off? Key on(or run)/off/acc? Does the radio work and sound ok?
Does the draw change with the volume setting?
I could only test the amp draw with the key out and everything off, my multimeter just doesn’t have the cajones to test while running. But the radio worked, the cd player was starting to have trouble recognizing burned cd’s but the radio itself seemed fine. I’ve gone ahead and purchased a new radio, today is install day so hopefully I won’t be posting something else in an hour. Thanks for taking the time to respond, it’s hard to find credible people and I appreciate it.
Is your radio supposed to play when the key is out? That’s never been the case in any of my cars. The key has always had to be in acc or on to play the radio .
**Ever since i went to cartoys and had a pioneer avh-x3800bhs stereo system installed in my car, my battery dies every 3 to days, it will be fine for a day, then the next, then all of a sudden the battery is completely dead, it even has a brand new battery in it… i am not understanding why it will do this only every 3 or 4 days, and what can the problem be? **
@todd.preston721 You have high jacked an old thread that already has two different posters asking questions so it will be too confusing to sort out what to reply to.
The real question is why are you not talking to the people who installed the system because only they can solve the problem.
You mean actually talk to someone face to face, yuk. No one does that anymore, it’s just sooooo '80’s. Nowadays if it can’t be done with a keyboard and screen, well, it just can’t be done.
Hi, I have the same problem as Conan. My car radio will keep playing even when I take the keys out and will drain my battery if left on. I will hit the knob to turn the radio off but then the clock will still be on. When I start my car the radio will not turn on right away and will take anywhere from 5-25 minutes to turn on. I also will use a cassette adapter to listen to music on my phone and it is having problems with accepting that as well. I’ve already drained two batteries while trying to fix this problem. My dad thinks that something may have gotten knocked out of place when I got rear-ended last summer.
Any knowledge on this helps 
You will receive better help if you start your own thread so the replies will be about your vehicle - what kind of radio you have and when problem started.
Car radio’s generally have two separate power input connections Ashley. One is connected to battery power all the time, and the other to a source only powered up when then key is in the acc or on position. The first is to prevent the radio from losing anything stored in its memory when the car isn’t being used, like preferred radio stations you’ve set, the clock, etc. The other is for powering up the radio & audio circuity so you can hear your favorite station or other audio source. Somehow you’re radio has got the two sources connected together internally, or the wiring to the radio has shorted the two together. It’s not possible to tell via the internet which of those two problems you’ve got. An auto electric tech would have to do some voltage probing. I suppose you could try replacing the radio. If that fixed it, that would prove it was the first problem. If it didn’t, the second.