No, not really. And if you have those fancy „keyless entry“ thingies, you are even more at risk as they can catch / expand the signal and send it to the car to open it.

And move your car once in a while, or otherwise make it look like someone is paying attention to it.

I had a car stolen: ten year old cheap econobox, over 100k miles, nothing in the car. I suppose it could have been an impulse, or it could have been that I had to move the car for street cleaning, left it in a bad spot (unlighted, no foot traffic, under a bridge) and left it there so I wouldn’t have to move it again for next street cleaning - the perils of living in a city and going mostly car free but not entirely giving up your car. Anyhow, I came back a week later and it was gone

Police were useless but offered the opinion that stripped parts for a ten year old econobox were valuable

I’m gonna make the assumption you live in the United States.

Anyone who steals something from inside your car Are typically opportunistic. Yes, there are people who make a living out of stealing cars and they make a living out of stealing parts of cars, but those guys tend to target particular vehicles and Particular parts ….tend to…

You said the alarm didn’t go off are you sure you didn’t accidentally leave the car unlocked?

Ways to prevent theft from your car:

• Always lock it
• Always park under lights
• Don’t leave anything of any value in the car that’s visible from the outside. If you have to leave valuables in your car, put it in the trunk
• If you can park your car in a garage
• Even putting a car in a parking lot that has some degree of perimeter fencing will deter thieves.
• Make sure the doors and windows all work properly. This may be obvious, but if you have a missing window, it’s an easy access or if you have a door that doesn’t lock properly, etc. etc.

Ways to respond to theft from your car.

• Report it to your insurance company
• Report to the local police department
• If you live in an apartment building reported to the landlord
• If you have things like a third-party GPS or other equipment in the car, keep the serial numbers and descriptions of those things in a folder in your house. My car got broken into you once in the The thieves stole my GPS. They cleaned out my change. I’d left some jewelry in the car. They cleaned that out. I reported all the police with the serial number and amazingly they recovered the GPS.

Finally car alarms are a waste of time.

Not a super helpful response, but honestly I’d be glad they only opened it. At our old condo people repeatedly broke into my wife’s car by smashing the window to steal random shit worth nothing, especially compared to the cost of replacing the window.

Don’t leave valuables in a car and people won’t break into it. Unfortunately that’s the best advice. Park where there’s good lighting. If you own the property where you park put up motion activated flood lights, but be mindful of your neighbors when you do.

Park under a lot of light. That’s pretty much it. And either have it spotless, like new car clean or full of trash. That’s what I would have avoided in the, very far, past.

I’m not proud of some of my younger years, but some things happened and now I do things to help instead of hurt.

Short answer- no. You can’t stop it.

Best advice is to not leave anything valuable in car, and nothing that could look like it’s hiding something under it or in it. Like no backpacks even if empty.

Ive lived in some areas where every night people would go checking car doors. Ive witnessed countless cars getting broken into just by people checking for unlocked cars. You’ll be surprised how often it happens even in areas where this is a known problem.

Otoh if the doors are locked but there’s valuables in sight then they’ll bust the windows which is why you shouldn’t leave anything in there to begin with.

My vehicle is camouflaged inside. Even low value belongings are hidden under trash.

Either they bypassed the alarm (there’s various hacks for various vehicles, but usually this is rare for petty thieves), or your alarm didn’t go off properly.

Either way, it doesn’t matter. Thieves are in and out in seconds and nobody except the owner gives a shit about a car alarm going off. You’re better off treating it like your car doesn’t even have an alarm.

The best way to avoid your car getting broken into is to make it less attractive than the cars around it. That’s not always easy, though, so it’s kind of useless advice.

I knew people once who always left their car empty. Privacy screen over the trunk/hatch was always open. Glove box was wide open. Ashtray and any places you could store spare change - wide open and obviously empty. They even left the fucking doors unlocked.

They never got broken into, but it must have been a pain to live like that.

I don’t know about stopping it if someone is sufficiently determined to get in, but if it’s a repeated problem, I suppose that you could put something that looks interesting to steal in the car with an AirTag-type tracking device or similar hidden in it and then provide the police with the thief’s track if they bite.

Putting visible cameras all over might deter some people.

I’d guess that parking in a garage would help, but you say elsewhere that that wasn’t an option here.

Twice in the past few years someone has gotten into my car and emptied my loose change container. Thankfully they didn’t mess with anything else. I just told myself they must need it more than I do.

This happened to me a couple of times when I lived in Rhode Island, but only if I accidentally left my truck unlocked. Then someone would steal whatever change was in there. Now I live in rural northern Maine, and I don’t even have to lock my front door, much less my truck. This probably isn’t very helpful; I’ll see myself out.

1. they cloned the radio signal that your keyfob sends
2. put a dummy in your car of a dude sleeping in the back seat

Are you sure it auto locks? The simplest explanation would be that you forgot to lock it, and it didn’t lock automatically. Maybe your home is close enough to the car that it still senses the key is nearby, so it won’t lock itself?

To answer your specific question, don’t keep anything visible in your car. Thieves usually only target cars that they can see have something inside.

A friend of mine used to live in a high-theft area and drive a “rag-top” convertible that he knew would be easy to cut open with a knife. So, he just left it unlocked, with nothing valuable inside, and nothing bad ever happened. A few times, he came back to find the glove box and center console had been opened. But that was it; the windows were never busted and the car was never damaged.

Don’t keep things in your car if you care about seeing them again, that’s about all there is to it. By the time even the best alarm system is activated, the stuff they saw and wanted is already gone.