Hidden 4th VIN on cars? Law & Order

I’m watching Law and Order Season 8 episode 11, in which a suspect has pulled a switcheroo swapping his car with identical make and model. The lab guys check to see if the standard three locations (dash, frame, engine block) of the VIN match. They do. But then we’re told that every car has a hidden fourth VIN tag that only the manufacturers know about. The lab guy says he had to drill a hole in the floor pan and use a dental mirror to find it.

So is it just fiction?

Don’t know the answer to that, but when I got HIN (Hull Identification Number) for my home made kayak I was told to put one plate at the right (port) rear, and hide the other.


Interesting. I built a cedar strip double paddle canoe, and in my state they only have you place one number on the hull.

There’s a VIN on the factory transmission too, isn’t there?

Wait, what? Is that required, or just a good idea? Cause if I ever finish my kayak, I guess I should know that.

There are VINs in lots of places on your car. That information is not readily available, for obvious reasons.

I noticed the VIN sticker of the hatchback door to my car. I don’t know if that’s a standard location or they just randomly put in on various locations of cars.

When I moved to California in the early 90’s with my car, there was an issue registering it at the DMV b/c it had been in an accident and the VIN on the replacement door did not match the one near the dash. The woman had to call a supervisor to look for a hidden VIN number, the location of which he looked up in a book based on the make and model and then poked around under the hood to verify.

When I took auto shop in high school, I found VIN numbers stamped on the frames of the cars we disassembled. It usually is there as components can be changed, while the frame cannot. Now where it is on every model of vehicle ever made, I don’t know.

However, an insurance investigator or a retired police officer who specialized in auto theft would probably be able to tell you.

It varies widely by state. Google it on your state’s DNR site.

Since this is about VINs and not the TV show, moved to GQ (from Cafe Society).

You may not have to worry about it, unless you watch NCIS, are building it in your basement and drink whisky from mason jars.

If you google ‘vin locations’ you’ll see that the automakers put VINs all over the place, and most cars have well more than four. There are also many things in newer cars that have non-VIN serial numbers that the manufacturer can cross-reference to what specific car they were installed in.

GM vehicles have always had VINs on nearly every major component, including things like fenders. Most Chevy/Pontiac muscle car aficionados are religious about the “matching numbers” thing.

I don’t think anyone else did that until much, much later - '90s, at least.

Then there’s the fun you can have with “constructed vehicles” that have been registered in three states… sigh

But then why would a NYPD CSU guy know them all? It’s hard to keep a secret if you tell everybody!

Though you can’t judge a 2000 episode by modern standards, I think the manufacturers put VINs everywhere now. I think they etch them in the glass, and probably as many other places as they can.

I take scenes like that as “TV shorthand”. It’s just a way to get something done quickly. As long as it isn’t incredibly stupid, I let it go. The plot point was, whatever the manufacturers do to identify the car, the crook missed one. I wouldn’t take “4 VINs” as a hard fact.

Automotive security used to be a major part of my interests, so I’ve paid attention to it over the years and used to receive things like insurance industry newsletters on vehicle theft and fraud.

It is a given that pros know everything any DMV or GTA squad knows; VIN locations, alarm wiring, key codes, etc. There are no “secrets” except for amateurs who can’t do much with them anyway. (The only “secret” that I know of use to the average car clout was that a particular year of Vette - around 1982, with the alarm key in the fender - could be taken by drilling a hole at a specific point and cutting the wire just inside.)

No manufacturer puts VIN or other numbers on the glass. It’s done by dealers at a whoppingly inflated price - a final upsell, often done on every car in the lot and then, gosh, “not optional” unless they want to wait for a special order. My Odyssey appears to have originated as a dealer-load special - it lacks not one option, has a number of add-ons (like mudflaps and a sunroof deflector)… and it has the original Texas plate number etched on every window. How useful. (Utterly useless, by the opinion of insurance/police pros, and I concur. But good for $3-400 to the dealer.)

Actually, the purpose of checking the VIN was that the driver was involved in a hit and run and he attempted to disguise that fact by purchasing the same model car in the exact same color and having the visible VINs changed. Unfortunately, the series did the usual L&O “leap of logic” by having the entire affair unravel by the dealer not change ALL of the VINs.

Anybody selling stolen cars in that price range would have changed all of the VINs and would have had access to the information to locate them to prevent this from occurring. Also, the suspect didn’t report his car missing and then have someone destroy it to ensure that it would never be found.

You know…TV thinking……

Ah, a 'roo. As in switche-.

Used to be a common way to steal and resell cars. Buy a total of some desirable model and take it to your “shop.” Steal a matching car and swap the VIN plates etc. onto it. Crush the wreck and sell the amalgamation as a “repaired” car.

Regarding home built boat HINs.
In Minnesota, you do need to register your boat (small sticker, not the 2" or whatever numbers), but a HIN was not needed unless the boat was titled or something.

But I went ahead and requested a HIN - it starts with MNZ
Here it is mentioned that you put the second one in a concealed location:

There is some debate about whether a home built boat needs a HIN. In my case it was just an email to the appropriate person so I played it safe


There’s a '50s Highway Patrol episode on YouTube in which the bad guys buy wrecks and steal matching cars. Of course it leads to murder because it’s Highway Patrol.

Little did they know that if they stole a '58 Vette it would be worth a zillion dollars 55 years later, just as they’re getting out of prison if they weren’t fried.