I've got a Hyundai Elantra 2000 model airbags need to replace driver's side seat belt was wondering if I have to disconnect battery or I can just unplug the seat belt

First have someone check the airbag system codes.The light will not stay out if there is a defect in the system.It's usually the drivers seat belt buckle or belt retractor switch.

check fuses and relays their are different locations for air bag sensors and their is also seat belt sensors and seat switches [check the connections under the seat ]---their are sensors under the front bumper behind the valance by the radiator support also if air bag curtains passenger side between inner fender, door and door pillar the following links have information or what to look for and assist in solving your problem the recall doesn't cover your vehicle but it pertained to the passenger air bag problem as well as the 05 posting
Why is my airbag light on 2005 Hyundai Elantra Air Bags Frontal Sensor Control Module Problems More than 280 000 Hyundai Elantras Recalled Over Air Bag Problems

Disconnect the battery negative terminal.
1. Wait at least 90 seconds after the ignition switch is
turned off and the negative (-) terminal cable is
disconnected from the battery before starting the
operation.
(The SRS is equipped with a back-up power source, so
if work is started within 90 seconds of disconnecting
the negative (-) terminal cable of the battery, the SRS
may be deployed).
2. Do not directly expose the steering pad, front
passenger airbag assembly, center airbag sensor
assembly, front airbag sensor, front seat inner belt
assembly, seat position sensor, occupant
classification ECU, front seat side airbag assembly,
side airbag sensor, curtain shield airbag assembly,
rear airbag sensor or front seat outer belt assembly to
hot air or flames.

2005 Towncar SRS Code 33 (3 flash + 3 flash, repeat this set for twice. then Beep 5 times pause x 5 = 25 beeps every 30min).

This means you have problem with left (Driver) side pretentioner (Seat belt retract system).
It doesn't mean physical belt or retract mechanism.It is just bomb wiring which is part of airbag system.
When airbag deploy, passenger must stay tight in seat otherwise body lean to front then slam back to seat by airbag.
if belt is loose or delay to lock, passenger's body rocks back and forth.So, system use small bomb (Fire power) to lock and retract seat belt when airbag deploy.There is small bomb and igniter in part of Seat belt retractor.
Code 33 is warning for this part on 2005 Towncar.(older model is different meaning in Ford/Lincoln, it's possibly passenger side airbag system for earlier model)
Before you work for any part of Airbag system and touch any "Yellow connector", * *Disconnect battery (negative side is good enough) and wait at least 5 min to clear all power in system**.(Airbag store back up power for few minutes to be able to deploy even in case if power disconnected)
by the way, you should move your driver seat most forwarded position before you disconnect battery to make it easy to work with seat belt.
locate driver side seat belt retractor (in center pillar between front and rear door, you may have to fight with weather strip)

Locate Yellow connector on bottom of Seat belt retractor (it's called "Pretensioner")it is located on very bottom of rear side of retractor.
only one yellow connector. (make sure your battery is disconnected)
Check its physical connection or looseness.if connection looks fine, you may have to replace whole seat belt ($180-$200 in Lincoln dealer)
You can check if pretensionor is good or bad by regular tester, but unless you know how, I won't tell (because I don't wan't you to blow out pretentionor).

Citrifical swicth is bad you'll have to replace the unit. carparts.com and search the junk yards marshalls in circilleville ohio has great service and prices.

For sure at the Hyundai Dealer.
You can try "junk" garages.
Last: You can buy some of the belt for towing from auto parts store or Home Depot and replaced. You have to stich very well at the ends. It is easy.

I would disconnect the battery minus - cable first, ensure the airbag connectors are the same ! otherwise I do not think you have a problem !!

dear friend-underneath the two front seats you will find connectors that forms part of the airbag system,disconnect the battery and then disconnect these plugs clean with contact cleaner and re-assemble,reconnect battery and check system.9 out of 10 times this will work,or ther is a problem with the module.

call the dealer ship there is a recall on airbags

2003 HYUNDAI TIBURON Recall ID from NHTSA: 02V290000 Auto Recall Date: NOV 05, 2002 Vehicle Component: SEAT BELTS:FRONT:BUCKLE ASSEMBLY Model Affected TIBURON Estimated Vehicles Affected: 7382 Recall Details Auto Recall Date: NOV 05, 2002

Vehicle Component: SEAT BELTS:FRONT:BUCKLE ASSEMBLY Estimated Vehicles Affected: 7382 Model Affected2003 HYUNDAI TIBURON

2003 Hyundai Tiburon Defect Summary:ON CERTAIN PASSENGER VEHICLES, THE DRIVER SEAT BELT BUCKLE WIRING COULD BE DAMAGED BY INTERFERENCE WITH THE DRIVER SEAT CUSHION HEIGHT ADJUSTER MECHANISM.

Defect Consequence:DAMAGED DRIVER SEAT BELT BUCKLE WIRING COULD CAUSE THE SEAT BELT WARNING LAMP OR THE SUPPLEMENTAL RESTRAINT SYSTEM (SRS) AIR BAG WIRING LAMP TO ILLUMINATE. IT COULD ALSO CAUSE THE AIR BAG FUSE (CAVITY NUMBER 5) TO OPEN, PREVENTING AIR BAG DEPLOYMENT. NONDEPLOYMENT OF AN SRS AIR BAG IN A CRASH WHERE AIR BAG DEPLOYMENT IS WARRANTED COULD INCREASE THE RISK OR SEVERITY OF INJURY IN A CRASH.

Remedy:DEALERS WILL INSTALL A NEW DRIVER SEAT BELT BUCKLE, IF NECESSARY, AND WILL PLACE A PROTECTIVE COVER OVER THE DRIVER SEAT BELT BUCKLE WIRING TO PREVENT DAMAGE FROM OCCURRING. OWNER NOTIFICATION BEGAN ON MARCH 24, 2003. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT HYUNDAI AT 1-800-633-5151.

Estimated Vehicles Affected: 7382

Notes: HYUNDAI MOTOR COMPANY 056