How to Open a Gas Tank Door From the Outside

We all are familiar with our common automobiles. Cars, vans, trucks, and other related vehicles have a gas tank equipped with a door at the rear of the vehicle. This metallic cover allows us to fill the fuel easily into the automobile’s gas tank without opening its entire body/unibody. It is fixed on a hinge and can be opened from outside so you can insert the nozzle of your spare fuel container into it while filling your car’s tank. Thus making things easier for you. Today, I will discuss how to open a gas tank door from the outside, which will help you whenever the door gets stuck.

How to Open a Gas Tank Door From the Outside

How the Gas Tank Door Gets Jammed?

The gas tank door can get jammed either from the inside, outside, or both. It usually happens when you try to open it and then push down on it instead of pulling up. This is a common reason why you need a key if using an older car that does not have power locks for its doors, although some models are still out there that do not have power locks at all, so don’t expect them to open automatically.

It Is Pretty Much Obvious What Causes the Problem but Here Is Other Reasons Why This Thing Can Jam on Your Vehicle

  • Hitting a curb -If a driver hits a curb, it can break off part of the gas tank door’s plastic mechanism. This then needs to be replaced instead of being repaired because it is easier to replace the whole thing than repair the broken part.
  • Stolen door -If your gas tank door is broken off, you will need to replace both the door and the gas cap. The gas cap can be easily damaged, so if it’s stolen, you should get a new one as soon as possible.
  • Modifications – If you have installed aftermarket parts to your car, such as an intake or maybe something else that you don’t really remember, the chances are high that it can interfere with the gas tank door because it is very close to where it needs to be for the door to open/close properly so try checking all possible sources for interference and then look for a way around them if they become a problem later on down the road. 
Car Hits Something Like A Rock Near The Front Tire

Step-wise Guide on How to Open a Gas Tank Door From the Outside: 

Step 1 –

To open the trunk of a car, look for the latch handle. It’s usually rectangular and located towards the side of the car that is closest to you. If you can’t see it, it may be because you removed something heavy from the car recently.

Step 2 –

Insert your key into the keyhole of this specific tank door. You can pull out any object for this step, as long as it has an edge for opening up locks (it doesn’t matter which one; even a screwdriver will do). After you’re done with this step, try turning your key around 360 degrees to see what happens. Also, make sure that you have the key in place for a long enough time.

Step 3 –

At this point, if you have successfully picked the lock using your chosen method, then there will be a ‘click,’ followed by some noise-making action on the door itself if nothing happens when you try to turn your key around, either give up or try moving it around while pressing down and holding it. This should work for those who don’t like messing with locks too much. There are several options to choose from here: (1) You could get lucky and open it up right away using one of these techniques; (2) You could keep trying different methods until something works out; (3) You can take off the fuel cap to open up the door, as it is often connected to a special lock (this might also work for some other car parts that are locked).

Step 4 –

If you can open the gas tank door from the outside, congratulations! You have just learned how to open a gas tank door from the outside. If not, try again or take off the fuel cap and do whatever needs to be done after getting rid of this extra lock.

Step 5 –

Close everything down, remove any long necklaces that could get tangled with anything else you didn’t close properly, and try starting your engine. After seeing that there’s nothing wrong with it, you should finally be able to go on a trip just fine.

If you have more than one fuel tank in your car, you will have to repeat the previous 4 steps for each of these tanks. Also, if you’re using this article as a guide for newer models (like those from the 21st century), then it may be safer to use your smartphone instead of trying out different methods with keys and locks.

Repair Gas Tank Door

Precautions While Learning How to Open a Gas Tank Door From the Outside

  • Be sure to turn the ignition switch OFF before starting work and pull out the key if it is an automatic transmission vehicle or just pulling out the driver’s side lock cylinder for a manual transmission vehicle.
  • Don’t get yourself burned by touching hot parts after opening the gas tank door from outside.  Do not touch something hot because there might be residual heat inside of car body due to electrical resistance heating in wires or contact points caused during short-circuit; also because you got your hands full with tools or since they could have been holding onto something that got caught on fire inside of car body as explained later in this article.
  • If you need to use a tool such as an iron bar or a pry bar, be sure to protect yourself from the possibility that you might scratch the car body.
  • Be careful of sparks when working with metal tools, and make sure you are wearing shoes on both feet so you can jump aside in case there is a short-circuit inside of the car body, as explained later in this article.
  • Don’t touch anything hot if it is non-conductive because it could cause electrical burns on your hands, such as plastic parts since they will not shield electricity like rubber gloves would do even if you are wearing them but be careful about crossing wires if they are still alive.

How Do Fix the Release Switch for Trunk of My Car? 

To Be Able to Open the Trunk From Inside You Need 2 Things:

  • Switch – located in car’s trunk somewhere close to fuel pump module (I couldn’t find mine, but still managed to figure out how to remove it). It has 3 wires connected leading up into the ceiling of the vehicle interior next to the lock cylinder for fuel cap – green(+), red(-), and black(ground) wire.
  • Key (that should be in ignition keyhole)
Lock Cylinder for Fuel Cap

Now Let’s Proceed to the Actual Procedure:

First, disconnect battery terminals on both sides of the car – it will prevent the computer from locking your trunk. Unfortunately, when I removed this thing, I didn’t have any wire cutters with me, so my ohm meter and quick thinking had to do the job (to find trunk release switch and fuse it).

Now you go under your dashboard on the driver’s side, where the lock cylinder for the fuel cap is located, and look in-ceiling right next to it for wires leading towards the rear part of the car interior. Black(ground) wire should be easy to locate since, most likely, the starter relay is being fed from that single black wire behind the lock cylinder into the engine compartment (non-lockable side). It’s a small circular box with metal brackets attached somewhere near the ignition coil or a similar electrical component.

Red and green wires are harder to locate, but one way to do it is by using your ohmmeter in continuity mode, which will blink a number telling you if there is a connection between ohmmeter probes.

You Can Check It Out to Tell if Your Gas Tank Has Been Tampered With

Useful Key Points:

  • To get the trunk open from the outside car, at least 1 of these 3 wires should be fused or disconnected from the PSU (power supply unit) or some other electronic box under your dashboard. For this article’s purposes, I will fuse red(-) wire with a black(ground) wire that looks like a power feed for ignition coils – an easy, clean, and fast solution.
  • Trunk release switch located in the trunk is being fed electricity through 2 different switches (mechanical and electronic), both of which will have to be bypassed/fused for the trunk to open from outside.
  • This procedure is useful for people who forgot the key inside their car, or someone locked it accidentally, did not have a spare key with them, etc.
Forgot the Key Inside Their Car


I hope the discussion stated above will help you learn how to open a gas tank door from the outside. Yous should be very careful about the fuel inside the car. As they are highly flammable so ensure proper precautions. Thank you, and have a good day!

Louis Wein

Louis Wein

Louis has always been fascinated by cars. He loves the way they look, the sound of the engine, and how they make him feel when he's driving. He is always keen to learn more about different mechanics of cars and how the engine contributes to other aspects of the car. As an automotive technician with over 10 years of experience, he knew how they worked and loved taking them apart to see how they went back together. He was especially interested in the mechanics of combustion engines and loved finding ways to make them more efficient. He loves to work on cars and help people keep their vehicles running smoothly. As a senior editor, he enjoys contributing to Diy quickly because it allows him to share his knowledge and expertise with others.

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