The seat belt in the van won't come out.

if it was mistakenly not installed at the factory you can get one installed or more likely it is under the seat somewhere.

What is the fault code, the sensor may not be the problem, it can be wiring and other problems

seat motor is no good and needs replaced if switch is working in each position

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).

below the link to fix the civic seat belt but you can request to fix your seatbelts it's 40 dollar and it will be working again

Put your seat belt on.step on the brake,you need a seat belt signal a brake signal so it will start

Hi, this is a generic problem with the car and once these belts is beginning to lock up, its almost impossible to free them. It's high time you visit the deal and preparing your mind to change it...

if you can pull the belt out, it should go back on its own, otherwise its a new belt,its a "no fix" item.

There is a tensioner pulley for each belt, you loosen the nut on the front of the pulley, then there is a tensioner bolt that you loosen, that will move the pulley away from belt to remove the belt. You'll need to get to them from the passenger side under the car. You'll need to remove the plastic covers to get them.

Remove the 4 bolts holding the seat to the floor and you'll have the clearance you need