2001+ Variant rear hatch unlock mod

[MidnightOil]

2001+ Variant Rear Hatch Unlock Mod

FYI, if you just want the mod info and aren't interested in reading about its history or possible alternatives, go ahead and skip down to the "Tools required" section below...

Before it was totaled in July 2004, the rear hatch lock on my 2000 GLX Variant (a late MY 2000, VIN > 320000, manufactured 03/2000) and I got along quite nicely: when I unlocked all the doors, the rear hatch unlocked as well and STAYED unlocked so I could open and close the hatch as many times as I wanted without having to "unlock" it each time.

While I was thinking about replacing my baby (RIP) with a 2005 Audi A4 3.0 Avant 6-speed, I just didn't want to spend nearly $40K on it. So, I found a used 2001 GLX 4Mo Variant (not a .5) with only 33K miles (an early MY 2001, VIN < 003000, manufactured 05/2000). Unfortunately, even though my new baby was only two months younger, we didn't see eye to eye regarding the rear hatch lock: I could only open the rear hatch within 2-3 seconds of unlocking it. I'd hear the same "ka-thump" as when unlocking the 2000, but instead of stopping there, I'd then hear a slow "bzzzzzzzz" for 2-3 seconds, after which the hatch would be locked again.

I even mentioned this strange behavior to the local VW dealer (Leith VW in Cary, NC), and they simply replied that it was "the way it's supposed to work" (theorizing that the change probably happened due to a lawyer requiring it for safety reasons). About a dozen or so frustrated CB5 and Vortex threads unhappily confirmed this.

While I'd seen the electrical mod this enterprising soul did on his 2004 Jetta wagon: http://www.4130-products.com/step/hatch/, three things led me to believe this was more appropriately a mechanical rather than an electrical mod:

1. The "bzzzzzzzz" sound was a bit strained, like there was something forcing the actuator closed after unlocking,

2. Unlock the hatch with the key, and hold the key to the left, the lock stays unlocked. If I slowly release the key, the plunger gradually closes, and I could feel some mechanical resistance, and

3. (This was the real clincher) Pulling the electrical connector from the lock actuator immediately after the unlocking "ka-thump" but before or during the re-locking "bzzzzzzzz" causes the plunger to immediately snap back closed.

This meant there was a spring, a magnet or some other fairly strong force acting to keep the lock actuator plunger closed (locked). Since it seemed obvious that nothing in the lock mechanism (outside the actuator housing) was doing this, it was time to go spelunking through the lock actuator, part 3B0 959 781 C.

As it turns out, the actuator contains a tightly wound spring, which when removed, eliminates the offensive auto re-locking behavior and leaves all other behavior unchanged. Read on below for the mod info.

However, instead of modifying the lock actuator, there may also be an alternative (which I can't yet confirm as a valid option). Searching Impex: http://www.worldimpex.com/ reveals four different SKUs when looking for:
3B0959781C
3B0959781B
3B0959781A
3B0959781

So, it may be possible to buy one of the "old" actuators for about $20-25 (or take one out of a wrecked 99 or 2000). However, it would be good if someone with a 99 or 2000 could confirm the part number on their lock actuator first. Otherwise, you can read about the mod below.


Tools required:

Philips screwdriver
Large and small flathead screwdrivers
10mm socket or wrench
Needlenose pliers
1 or 2 small zipties

Time required: about 1-1.5 hours, going slowly and carefully.

Disclaimers:

Proceed at your own risk. I cannot assume any responsibility for any damage, injury or other consequences as a result of anyone following these instructions. This information is supplied to inform others about what this modification to my personal vehicle involved. If you would like to make such a modification to your own vehicle, please stop and seek the advice or assistance of a qualified mechanic first.

This procedure describes parts present on a 2001 hatch. The Bentley shop manual shows a very different lock carrier assembly for 2001.5+ hatches, so these steps may need to be modified accordingly. However, in both cases, the lock actuator (motor) appears to be very similar, as are its mounts and connections to the lock mechanism.

Since I don't have a digital camera, I swiped and annotated a good picture of a sedan lock assembly from VWfool2000's microswitch writeup, so full credit for this picture goes to him:
http://www.cincodigital.com/vwstuff/switch_mech02.jpg

then I just made a separate drawing of the lock actuator internals.


Steps:

1. Open the rear hatch and manually close the latch so the rear dome light won't stay on.

2. Remove the lower hatch trim by removing four Philips screws (two exposed at the top edges of the panel, and two concealed in the handles--pry out the plastic cover caps with a flathead screwdriver first), then pry off the 12 clips around the edges (4 on the top edge, 4 on the bottom edge and 2 on each side). Reach underneath the bottom edge and work around each side to the top, feeling for and pulling the clips loose one at a time. These are metal clips just like those under the door sill (scuff) plate.

See:

3. Disconnect the latch operating rod from the latch. Push on the bottom side and it will pop out of its plastic retainer. Rotate the rod out of the way, making sure not to twist it, which would lengthen or shorten the rod.

4. Disconnect the lock actuator and lock cylinder electrical connectors. Just squeeze the actuator connector, and use a flathead screwdriver to lift the tabs on the cylinder connector.

5. Remove the two 10mm nuts holding the lock carrier assembly (the metal frame that holds all the parts except for the outside handles).

6. Release the lock cylinder by putting the large flathead screwdriver under the bottom edge of the retaining clip (a square C-shaped metal bar that goes across the top of the lock cylinder and down both sides), then twist the screwdriver counterclockwise. Hold the screwdriver in place (jiggle it a bit or try a couple of times until the clip releases) and pull the entire lock carrier assembly off. The retaining clip remains attached to the lock cylinder.

See:

7. Remove a ziptie holding one of the wiring harnesses to the lock carrier. Replace it when reassembling.

8. Turn the carrier over and remove the two Philips screws securing the lock actuator to the carrier, then remove the actuator. Rotate the actuator slightly to help detach the circular plastic clip connecting the actuator plunger to lock mechanism.

9. Turn the actuator over and see the part number and manufacture date printed on the top (mine is: 3B0 959 781 C, manufactured 31.03.00 16:52). Using a small flathead screwdriver, start working a couple of the 8 tabs out of their attaching slots. Take plenty of time here...being careful makes it possible to release all of the tabs without breaking any of them. After getting a couple started, insert the screwdriver in the opening between the top and bottom halves of the case and twist gently to release the other tabs. Work around the case a couple of times and twist a little more each time until all the tabs are free, then remove the top half of the case. There will be a little bit of resistance from the two rubber washers that help isolate the long cylindrical nuts for mounting the actuator to the lock carrier assembly, but they should stay in place as the case opens.

Be very careful not to accidentally release the spring at any of the next couple of steps. It's strong enough that it could lash out and poke someone in the eye, but it doesn't seem strong enough to cause any serious injury if it were to hit an arm or leg.

See:

10. Remove the plunger, large plastic gear and spring as a single assembly.

11. Pull the spring assembly (with its plastic frame) off the end of gear, while holding the spring in place. Make a note of how the plastic frame is oriented (which end faces up, and which side faces the gear).

12. While still holding the spring, grab the spring with the needlenose pliers and pull it off the side of its plastic frame. Hold the pliers at an arm's length, looking at the side of the spring like the letter O, then slowly release the pliers and let the spring expand. Discard the spring.

13. Put the plastic spring frame back on the end of the gear, orienting it as noted in step 11 above.

14. Reinstall the plunger, large gear and plastic spring frame back in the actuator housing. Make sure that:
a. The head of the plunger is in the semi-circular notch in the side of the actuator housing,

b. The square tab at the foot of the plunger (near the large gear) is in the groove in the bottom of the actuator housing,

c. The large gear meshes with the small gear on the end of the motor spindle, and

d. The plastic spring frame slides back in to the two plastic slots in the bottom of the actuator housing.

15. Snap the top half of the actuator housing back on.

16. Temporarily reconnect the lock actuator electrical connector and lock and unlock the rear hatch with the key, the remote or the driver's door switch a couple of times. When unlocked, the plunger will stay open (extended). When locked, the plunger will stay closed (retracted). After testing the mod, disconnect the electrical connector again.

The hard part is done. Time to reinstall everything back in the car.

17. Reattach the lock actuator to the lock carrier frame using the two Philips screws removed in step 8. Make sure to reattach the circular plastic clip connecting the plunger to the lock mechanism.

18. Position the lock carrier over the two bolts where holding the two 10mm nuts from step 5, and make sure the lock cylinder lines up with its opening (this is where the cylinder sticks out through the back of the hatch to accept the key). Once the lock cylinder is in place, press on the lock carrier to snap and lock the lock cylinder in place. This is snapping the lock cylinder retaining clip released in step 6 back in to place.

19. Reattach the two 10mm nuts removed in step 5.

20. Reattach the two electrical connectors disconnected in step 4.

21. Reattach the latch operating rod disconnected in step 3. Just swing it back in to place and snap the end through the top of its circular plastic retainer.

22. Replace the ziptie removed in step 7 with a new one.

23. Before replacing the lower hatch trim, test the entire mod by manually pulling the handle on the outside of the hatch, and the latch will open when the door is unlocked. Make sure to pull the handle at least once before closing the hatch to open the latch manually closed in step 1. Leave the hatch open and look at the lock mechanism to see the metal pin that gets pushed back and forth. Pulling the door handle with the pin in the locked and unlocked positions will show how unlatching the door is completely mechanical at this point.

24. Reinstall the lower hatch trim by reversing step 2. Start at the top and snap the clips back in to place, working around the sides and to across the bottom edge. Replace the four Philips screws and the two plastic covers in the handles.

Finished. The rear hatch lock now works just like all the other door locks.

-Nick

[Rusty]

Wow, you've really been burnin' the midnight oil, haven't you?

We'll leave this here for awhile to promote discussion and questions, and then move it to the Info Forum. Thanks!

[vwagen]

If someone could confirm this works on b5.5's as well, it would definitely be worth mentioning - including any differences from the above write-up.

This mod could make a bunch of variant owners very happy!

[billyvw]

I second the B5.5 version. The relocking drives me nuts.

[MidnightOil]

Well, from my perspective, the two most important things to confirm for the B5.5s are:
1. That the re-locking has the same cause: stand behind the rear hatch and unlock it with the key or remote. Do you hear a "bzzzz" sound for 2-3 seconds after unlocking, and is the hatch locked again when the sound stops? If so, it's almost definitely the same cause.

and

2. Remove the rear hatch trim, find the lock actuator and read the part number. If it's the same as for my 2001 B5, then you're good to go with the mod.

I'd be happy to help someone with a B5.5 variant around Raleigh (or pretty much anywhere in the triangle). Just let me know.

-Nick

[quality_sound]

I wish I was in NC, I'd be there in a second.

[dgabler]

with my 01.5:
unlock hatch through remote or door. no sound. if through remote lights flash.
press lever as if pulling up door. Hear a kerchunk, ala mechanical jaw releasing.
Lever for door is afaik is just a switch.
When shutting door no noise other than normal closing noises.

Oh fwiw if you apply negative voltage to the tailgate switch you will actuate the mechanical jaw. which will start to open the gate but not fully do it.

[MidnightOil]

Hmmm...after reading dgabler's last comment and studying the Bentley B5.5 lock mechanism drawing more closely, I'm thinking this mod will NOT work for the B5.5s. Here's why.

The "kerchunk" dgabler describes is the lock actuator. On my B5, this happens immediately upon unlocking, but it only happens when he pulls the handle to open the hatch (after unlocking) on his B5.5.

Looking at the two diagrams, it seems that the B5 and B5.5 rear hatch unlocking differ in the following ways:

B5: lock actuator extends to unlock and retracts to lock, which moves a pin that later gets pulled mechanically by the handles to pull the operating rod and open the latch, releasing the hatch to open.

B5.5: lock/unlock must only be a "logical" unlock in the CCM (no sound). Later, when someone pulls the handle, the lock actuator extends, goes through a "reverser", and pulls a cable to directly open the latch, releasing the hatch to open.

Based on this observation, I'm guessing that all 2001 B5s ended up with the B5.5 lock actuators as a matter of production convenience, since the spring to retract the actuator plunger would be desirable in the B5.5 design to release the cable.

It also seems to me that VW made this change for two reasons:
1. The B5 sedans have two actuators: one for locking/unlocking and one to remotely open the trunk. The B5.5 design effectively allows for both operations with a single actuator. This also means an identical setup for both sedans and variants.

2. Only powering the actuator when opening the rear hatch should increase its lifespan and decrease the number of service problems. If an average B5 locks/unlocks 4 times a day, 5 days a week, 50 weeks a year (1,000 actuations/year), such as one drive to work and one home again, but on average people only actually open the hatch twice a week, 50 weeks a year (100 actuations/year), then all else being equal, one would expect the B5.5 design to last about 10x longer.

So, I think I understand more clearly what's going on now and based on what's outlined above, believe that the mod I've described will only be useful for 2001 B5s plus any 99s or 2000s that have had lock actuators replaced with newer parts.

I'll definitely be curious to see what dgabler's solution ends up being in: Variant tailgate question