One out of the four spark plugs in my 2013 Hyundai accent is not firing, the battery drains when parked overnight. they say it is the brain brain box. who can repair it or how do I get another on?

In this link, also known as 'firing order'.

https://www.google.com/search?q=2002+hyundai+accent+spark+plug+lead+diagram

..

that bad act blows up elecronic's (bbbbbbad to the bone)
reverse polarity jumps.(ouch)
unplug the dead YAM BAT overnight,(battery NEG lug pulled
and pray that next day it works.
it is true some electronics do have this protections but no all.
the battery pull does the super secret trick of .....
most chips made have latchup feature and the only way to unlatch that
is battery pulled , for long time. overnight.
or even remove both LUGS and short them now. (lugs not bat)
the systems have CAP's and the goal here is get them all below.
0.3vdc, (fully discharged to 0v or very close)
then they unlatch the protectors.)

5/8 deep not box sore deep they are not deep enough. socket
https://www.partsgeek.com/catalog/2004/hyundai/accent/engine_electrical/spark_plug.html

How to change spark plugs hyundai accent 01 - 05 - YouTube

? 3:18
https://www.youtube.com/watch?v=tU2vwisJ7v4
Feb 16, 2012 - Uploaded by PNBNC
I filmed this right after changing my old plugs, I figured it was easy enough to film and some people can profit from it. for a ... Coil, you mean wire lol ... When you go to put the spark plug back in, never start it with the ratchet.

How To Replace Change Install Spark Plugs 2001-06 ...

? 3:17
https://www.youtube.com/watch?v=yVV2KcPDFIo
May 14, 2013 - Uploaded by 1A Auto Parts
... spark plugs. This video is applicable to the 2001, 2002, 2... ...spark plugs. This video is applicable to the 2001, 2002, 2003, 2004, 2005, 2006 Hyundai Elantra 2.0L. ... +queentonks A little know-how can go a long way. We're glad ... When do you think is good to replace my spark plugs wires? My spark ...
2001 Hyundai Accent Firing Order: Engine Mechanical ...www.2carpros.com/.../hyundai-accent-2001-hyundai-accent-firing-orderApr 23, 2009 - Engine Mechanical problem 2001 Hyundai Accent 4 cyl Two Wheel Drive Manual 95000 ... Now I'm trying to figure out how they go back on. How do I find out the Engine Firing Order for my car - Hyundai Accent 2001 1.5L?Which is cylinder 1 - 1.6 Accent - Hyundai Forum: Hyundai ...www.hyundaiperformance.com/.../16837-cylinder-1-1-6-accent.htmlJan 13, 2003 - 3 posts - ‎3 authorsFrom what I read though, the coil pack is configured as 1 4 2 3. I'm assuming the first wire on the coil pack goes to cylinder 1. Can anyone ...

Hyundai Accent How to replace spark plugs - YouTube

? 3:21
www.youtube.com/watch?v=TQSplCznN9c
Jan 15, 2014 - Uploaded by Dima Travnev Hyundai Accent How to replace spark plugs ... Part 1 2009 Hyundai Accent tune up Spark plug replacement in 720pHD - Duration: 14:00. by ...

fix it2011 should be under warranty yet go to the dealer you bought from and demand they

most hyundais are a 16 pin conector located under the steering wheel somewhere (fuse box, under dash, behind panel right hand side of steering wheel) or in the centre under the handbrake or just behind park brake under a cover.

ECU =ENGINE CONTROL UNIT.
it is the computer,the brain of the car or truck,
it runs every electrical sensor and spark plug
ignition and fuel system its what give u the codes
when something gos bad
and if the ECU is bad the car may not start

Have a look at the plugs, may be dirty or faulty. Look for cracks in the distributor cap.

Another person had a similar issue with their 2003 Hyundai 1.6L engine. Their fix after looking at many things was that their ECM relay had gone bad. The relay is located in a box under the hood. The box has fuses and relays ... usually there is a legion or map of what is where on the underside of the box cap/lid. The relay is about the size of a one inch cube.