2002 Suburban seat belt tensioner

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).

possibly there is something stuck in the belt not letting it retract

have a look to see if its coiled in twisted as you pull the belt out if the buckle doesn't line straight to the female end well its probely retracted in twisted to repair pull the belt out all the way and then realign the belt its quite hard to do so take your time hope this helps.

there is a pulley on the right side of engine (as sitting in drivers seat) it is either a 15 mm bolt used to rotate or a three eiths square drive and rotate tension off the belt

sorry. only answer is replacement.(no user seviceable parts inside.)
bet that dont get me 4 stars.......

My 97 did the same, it was just dirty in the seal belt wind up mechanism.

I just solved the problem for a stuck rear center seat belt in my 2002 Jetta.

Flip the base seat cushion forward against the front seat backs. Trace down along the belt to its tether point on the floor. The belt is sewn around a steel loop. The loop is anchored to a black steel hook. A thin silvery retainer plate is spring tensioned on top of the loop to prevent it from sliding off of the hook when the seat back is folded.

Therefore, you need to press the silvery retainer plate away from the hook (push up) to allow the loop to be slid from the hook. The belt was tight with the seat back in the upright position, so it was necessary to fold the seat back forward to create slack in the belt. Now push the belt loop towards the trunk and slide it off of the end of the hook (only possible with the retainer plate pushed up out of the way).

Now with total release of tension on the system via the bottom end of the seat belt being untethered and with the seat back returned to the upright position, normal extension and retraction of the belt will be reestablished. Next, simply extend the seat belt and slide the loop back into place over the floor hook. It snaps past the silvery retainer plate without all the effort required to hold the plate up during removal of the loop during disassembly.

Check again, the seat belt should be extending and retracting properly. Now just put the seat cushion back into regular position and you will be able to safely buckle up three people across the back seat.

It took about as long to do this repair as it has taken to post this answer to the problem. Note, the seat belt safety mechanism only allows normal extension and retraction of the belt when the seat back is upright.

You'll have to remove the trim on the side of the car in order to access the seat belt tensioner. You can adjust it with a screw driver and retract it back..

The mechanism that allows it to retract is broken. Replace the seat belt.

Try giving it a solid tap with something hard (screw driver handle) while jiggling the seatbelt.