I'm a car expert

A CAR expert has been called a lifesaver after showing people a trick to unlocking your car when the battery is dead and your keys are inside.

Juan Banuelos is a car enthusiast who posts videos of himself messing around with vehicles in the hopes of passing on handy tips and tricks.

In one video on his YouTube channel (@JJBanuelos) Juan showed drivers how to unlock their car when the battery is dead.

He explained that after seeing the lights on the truck flashing for no reason, his brother disconnected the battery and closed the hood, and locked the doors with the keys stuck inside.

Juan showed viewers how he could get back into his truck to re-connect the battery with just a jump box.

This saved time and money as he did not have to break his window or grill.

Using a GB40 Noco Genius Boost from Amazon he unlocked his vehicle, noting that jump leads could also be used with the same method.

The YouTuber clarified that his method only works with vehicles where you can access the starter underneath the car or truck.

Juan went underneath the passenger side and identified the starter where there are three wires: red, a smaller solenoid wire, and a ground wire.

He attached the red cable to the connector on the first wire and then he connected the jumper cable to the ground wire.

"This will work on any make or model guys - all the starters are going to be the same," he said.

Once the connections were made, he then got the jump box and turned it on, making the box take the place of the battery.

He then got his keys and pressed the unlock button before going back to the door and easily opening it.

Viewers were astounded at the hack, with many coming across the video in their hour of need.

"Man. You saved me a lot of work. I did the same thing you did. Was back in my truck in about 10 minutes. Thanks a million," one wrote.

Another commented: "You saved me. Driving a rental. The thing was packed with groceries and the doors just locked us out.

"Took maybe 5 minutes to pop the lock. Wife was still on the phone with triple a. Thanks!"

A third said: "Great info. I’ve been a car guy for over 50 yrs. And never knew this."

Meanwhile, another car enthusiast correctly guessed that previous damage to the driver's door meant that the manual key did not work to unlock the door.

He said: "I would guess that you had collision damage to the driver’s door or a driver’s door handle removal in the vehicle history.

"The metal key should always lock and unlock the driver’s door without any power.

"Incomplete reassembly after body work likely left the metal key backup mechanism not properly connected."

Juan replied: "Yeah, you're actually correct it was in a small accident before. The body shop that repaired the doors did not repair the lock mechanism correctly."

Another viewer suggested using the same method but connecting it to another part of the car.

They said: "Could also do the same thing, but on the alternator if that is more accessible."