Car stereo not working right in cold weather

One cold morning, I started my car and noticed that the stereo’s lights were on but no sound or display. I drove it to work. When I turned off the car, the stereo’s lights were still on. I closed and locked the doors, but the stereo’s lights remained on. No sound or display, but the lights never turn off? I took face off the stereo and warmed it up at home. Tried it the next day, but it still doesn’t work.

it’s probably in the body of the radio. There’s likely a bad solder join or a loose wire, and the cold makes it lose contact. It happens in aging vehicle electronics. They’re exposed to a very harsh environment for circuitry.

This is an after-market stereo (4 years old) with a removable face. The car should cut power to the stereo when turned off, shouldn’t it. Or does the stereo handle that? Why do the stereo’s lights stay on?

Generally stereos have two power wires going to them. One cuts off as you say when the engine turns off. The other is a constant-power wire that keeps power going even when the engine is off so that it can store your radio presets, EQ settings, etc. It’s not unheard of for the constant power and the switched power circuits to get bridged, making the constant power wire also power (or sometimes partially power) the switched side.

I’d pull the fuse for the stereo, and also the fuse for the cigarette lighter or accessory circuit that is powering the second power input, the one that is on all the time on the stereo. I guess you’ll know when you have the right one if the lights go out. Then replace the accessory fuse and stereo fuse in that order. Now see if your attempt to reset it worked. If you’re lucky, that’s all it needed.

If not, it will likely be cheaper to junk it and get a newer and better stereo than to try to fix this one. It sounds like more of a malfunction than something caused by the cold.

Thanks, but the car died. This is a 2001 Neon with power locks, so now I can’t open the doors because the battery is dead (everything electric). So I can’t even change the battery or pull the fuses. Anyone know how to open a Neon with power locks and no battery power? The key is useless because the lock is powered.

You should be able with a little effort open the hood manually and get a charge on the battery, then disconnect and replace the radio making sure the constant voltage is on the correct connection. Follow the cable from the interior hood release and figure out how to activate the hood release manually.

Typically using the key in the door will manually open the lock… Unless something is damaged.

Got it open. The passenger door opened with the key - driver’s side seems to be completely electronic. Now, should I pull the fuses, replace the battery, and replace the stereo, or should I call AAA to tow it to a mechanic to check the wiring and electric system?

No, you should pull the fuse for the stereo per the previous instruction, charge the battery, preferably with a low amp charger overnight, start the car in the morning and see if the battery light on your dashboard is lit. If it is not, you should run the car in the driveway with every appliance and light and whatever on and turn the car off after an hour and let it cool all the way off and try to start it.
If it seems sluggish turning over or just clicks, replace the battery (yourself), drive the car to a mechanic and check the alternator (or if you can do it yourself, remove the alternator and bring it to a parts store or chain that can bench test it).

Keep the stereo until you do these things. Your aftermarket stereo’s weirdness is probably the result of a bad battery and alternator, not the problem.
The lights that are staying on are LED and should take a week if the car was sitting in cold weather to make a difference. I bet that you need to change at least the battery and maybe or the alternator, and when you do the stereo will go back to normal.

I took the face off, and used the reset button my head unit started working again. It was staying on even when I pulled the fuse, and no buttons were working. Sound was working, because it was already on a certain level, but I couldn’t change anything.