[Velocity]

My rear hatch does not open via the switch in cabin under dash OR via the key release at back of car.  I cannot hear a motor running when I do either.   I can (thankfully) open the hatch via the wire loop behind the rear carpet (so all the "mechanics" of the bar/latch pins/etc are ok).   

 

I've read all the other threads I could find on the forum on this topic so I think I've done the basic troubleshooting.    I've checked fuses, cleaned the ground inside the car near the hatch lock (shown below with green vertical arrow) and verified none of the various electrical plugs/connectors in the hatch area are disconnected.

 

I cannot, for the life of me, seem to find where the actual hatch release motor/actuator itself is located.  I'd of assume it'd be below one of the hatch pins assemblies (left one shown below with horizontal arrow) and/or attached to the bar that releases the pins, but I don't see anything there that resembles a motor.    I read in one of the other threads you had to "remove a protective panel" to access it?    Can anyone give me a better description of where the hatch release motor is located?

 

   

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[Waylander]

See that bit of cashmere carpet on the right in your photo, under that you will find a plastic trim / shield held on with 3 - 4 self tapping screws, remove that and the motor will be revealed

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[J.Elenbaas]

I have had the same problem, the electric motor was the problem.

Replaced with a used one from the Bay, and all good again.

 

The old one is still around for repair, but had no time yet.

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[Roboman]

Velocity I have just sorted mine so lifted my post from "what did you do for your 968 ...". You didn't mention you'd checked the footwell switch for correct functioning, so ....


Boot/trunk lock now works. Two problems:

1. The footwell switch. It acts as a junction box as well as a switch, but both through the connecter writhin the switch. The rocker had become asymmetrically worn and sloppy, and wasn't connecting either the junction or switched point. The asymmetry is because the spring loading is to one side of the rocker. Inexplicably there is an identical hole for that spring on the opposite side of the rocker. The solution was to remove the rocker top, swap the spring into the other hole, and turn the rocker around and relocate it. Obviously taking the opportunity to clean and lubricate the insides of the switch. It feels sharp now, but the next time it goes sloppy it will need a new replacement.


2. One of the contacts within the release motor actuator had spread, moving partially off the metal contact and on to the plastic. There was also a lot of grease over everything inside the housing. After typical cleaning and bending, all rotates smoothly and reliably.


Velocity the release motor is attached to a strut on the LH side as Waylander indicated. You can easily check functionality after removal by holding the casing of the motor onto the Neg side of your battery, and then using crock clips from battery pos to actuate the motor.


Red ... drives the motor and then stops when it reaches its parking point; same as wiper motors.

White and/or brown .... Drive the motor continuously.

Blue ... That pin is a junction point and doesn't feed through to the plastic cover.


Hope this helps

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[Velocity]

Velocity I have just sorted mine so lifted my post from "what did you do for your 968 ...". You didn't mention you'd checked the footwell switch for correct functioning, so ....


Boot/trunk lock now works. Two problems:

1. The footwell switch. It acts as a junction box as well as a switch, but both through the connecter writhin the switch. The rocker had become asymmetrically worn and sloppy, and wasn't connecting either the junction or switched point. The asymmetry is because the spring loading is to one side of the rocker. Inexplicably there is an identical hole for that spring on the opposite side of the rocker. The solution was to remove the rocker top, swap the spring into the other hole, and turn the rocker around and relocate it. Obviously taking the opportunity to clean and lubricate the insides of the switch. It feels sharp now, but the next time it goes sloppy it will need a new replacement.


2. One of the contacts within the release motor actuator had spread, moving partially off the metal contact and on to the plastic. There was also a lot of grease over everything inside the housing. After typical cleaning and bending, all rotates smoothly and reliably.


[...]

 

I wound up getting a known-good release motor (ironically, from one of the previous owners of this car) - swapped it out tonight, and......nothing.   Still not working off either the key lock OR the footwell switch.

 

I'll take a look at the footwell switch next.

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[Waylander]

Just a stupid question, have you checked the fuses

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[Roboman]

Velocity, assuming as Waylander says, the fuses are okay .....


Now that you've found the motor you can test your circuit at that junction ....


Red .... 12v permanently ..... that's the parking line.


White or brown .... 12v when the footwell switch or boot key are used (ignition on for footwell)


Diode .... 0.7 in one direction, OC in the other ....


I've just thought .... Did you test your new motor in situ? If not, did you attach a line from the motor casing to the car chassis? If "no" to both of those questions then you need to attach an earth line. Then make sure the motor terminals or rotating arm won't foul on anything and test again.


if you need to take out the footwell switch it requires a bit of grunt. There are two fairly large spring clips on either side of the plastic surround .... a panel lever is helpful if you have one. Don't panic if one or both of the clips fall off as you drag it out of the hole, the recess behind the switch is fairly shallow and you can just reach behind and pick it/them out.


I'm assuming you have multimeter ... the contact layout is marked on the side of the switch, if your switch isn't working correctly (contacts not good or rocker not clicking back properly) you will need to replace or repair as I have indicated. If you want to repair (there's not much you can do apart from lubricate, clean contacts, and rotate the rocker), then beware as you lift off the rocker as there is a spring below.


good luck

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[Velocity]

Velocity, assuming as Waylander says, the fuses are okay .....


Now that you've found the motor you can test your circuit at that junction ....


Red .... 12v permanently ..... that's the parking line.


White or brown .... 12v when the footwell switch or boot key are used (ignition on for footwell)


Diode .... 0.7 in one direction, OC in the other ....


I've just thought .... Did you test your new motor in situ? If not, did you attach a line from the motor casing to the car chassis? If "no" to both of those questions then you need to attach an earth line. Then make sure the motor terminals or rotating arm won't foul on anything and test again.


if you need to take out the footwell switch it requires a bit of grunt. There are two fairly large spring clips on either side of the plastic surround .... a panel lever is helpful if you have one. Don't panic if one or both of the clips fall off as you drag it out of the hole, the recess behind the switch is fairly shallow and you can just reach behind and pick it/them out.


I'm assuming you have multimeter ... the contact layout is marked on the side of the switch, if your switch isn't working correctly (contacts not good or rocker not clicking back properly) you will need to replace or repair as I have indicated. If you want to repair (there's not much you can do apart from lubricate, clean contacts, and rotate the rocker), then beware as you lift off the rocker as there is a spring below.


good luck

 

Regarding Fuses - according to fuse box decal - Fuse 1 has "tailgate unlocking" (as well as sunroof), Fuse 28 is listed as "switch tailgate unlocking" - both fuses looked fine visually (no "break" in fuse), tested fine in the "test relay" in fuse box (green light came on) and sunroof motor runs fine (also on fuse 1).   While likely not relevant, my rear wiper was removed (hole is plugged and wire is taped off) - that's also on fuse 28.   Unless there is some additional fuse (or relay? - relay "G3" is listed as "rear window" - wonder what that means?) involved anywhere, I think that part (hopefully) is ruled out.

 

Regarding the motor - I didn't do an independent test of the new motor, but the person I got it from stated it tested fine in their 944 S2, and I trust them.    Will likely add testing the original motor (now in a bag) to my to-do list, since it's out of the car.   If the original motor tests OK, that'd point me to a root cause other than the motor.

 

Thanks for the layout of the wiring for the motor and for instructions/hints on the footwell switch - I'd glanced at that switch and it didn't look like it'd be a simple job.   The switch "feels" good (ie, smooth motion, solid "click" when it engages/connects, so I'd placed the switch lower in my "testing list".

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[Waylander]

Rear Window = Heated Rear Window

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[Velocity]

OK, finally (mostly) have a fix/resolution to this issue.   Decided to document (with pictures!) the rest of my journey in case it helps others :

 

First off, removing the footwell switch - used trim removal tools on both sides (front and rear) to "pry" it out. Both metal pieces (that latch it in place) came out with it, no real difficulties there.

 

Managed to get wiring out enough to unplug it:

 

   

 

Once I had the switch out, I brought it inside to disassemble/clean it.  Here's the switch (still in the surround trim, facing down) :

 

   

 

I noted a bit of corrosion on the "clips" (orange color on bottom of switch in this pic) that hold the switch in the trim piece, but wasn't too concerned about that as it should affect the switch function.   Side note - I checked several used switches on ebay and most seemed to have this same corrosion on these clips.

 

You can remove the switch from it's "surround trim" by pushing it from the front back thru the trim.   Once separated from the trim, you can pry the "front" of the switch off and which reveals the small metal piece that acts as the "actuator" :

 

   

 

The small metal actuator piece just falls right out of the switch (small piece of metal in middle of below pic is the actuator- switch faceplace upside down on right)

 

   

 

Once I had the switch disassembled to this point, I didn't go any further.   I used deoxider spray thoughout the swtich and plug - anywhere i could get to metal, I sprayed and cleaned up the excess.

 

Once I reassembled the switch (all parts just snap back together - metal actuator back in switch, faceplate snaps on front of switch, switch snaps back into trim surround) I took it back out the car, plugged it in, and pushed it back into the wall of the footwell.   For whatever reason I could NOT get the bottom driver-side clip to snap back in fully, but the switch was securely in place, so I tested the switch itself, and....

 

SUCCESS!     I could hear the motor in the hatch running!     :clap:   

 

I did have to make a minor adjustment to the motor itself - for whatever reason, the replacement motor I had installed had the "arm" facing the front of the car - which didn't allow me to reattach the cable.  I'd intentionally left it like this after the motor replacement as it didn't really matter given I couldn't activate the motor anyhow.

 

   

 

Luckily, the arm can be removed (10mm nut) and adjusted to proper rear-facing position.  I did this and attached the cable.    You can see the small "cutter pin" type attachment on the end of the arm that holds the cable in place on the arm - this piece is removed in the above pic, but attached in the below pic. 

 

Losing this piece has been a problem for others, so it being in place is something to check if your motor works, but hatch doesn't release.   If the piece has fallen off the arm, it's likely in the metal well area under the arm (which is sealed, so it should be caught there. 

 

   

 

I did another set of tests opening and closing the hatch once cable was attached - still worked fine. 

 

Next test - opening using the key in the lock on the back of the car.    This did NOT work.   I've read elsewhere the problem is usually in the key switch actuator that can be seen from inside the car (hole on interior of frame with gasket and wires from the lock actuator coming out of it) - here is a pic of mine :

 

   

 

The round white plastic piece with the grease on it rotates when the key is used on the rear lock,activating the switch on the left side (well, actually right side since the picture seems to be flipped vertically) side of the the pic.   I could see it working fine when rotating the key, but the motor did not actuate.   I cleaned the grease up a bit, cleaned the switch as best I could without removing it, and used the deoxider spray on the switch and the connector plug.  After I reconnected the plug, I tested again - still nothing.    Went back to interior and tested with footwell switch, now IT didn't work again.   :whine:

 

After collecting my thoughts for a bit, I went and checked the fuses.    Fuse 1 had blown somewhere in my cleaning of the switch.   Replaced Fuse 1 - tested from footwell switch, motor worked again (YES!).    Holding my breath, I tested rear lock again - still nothing.     Tested footwell switch (wondering if I'd just blown the fuse again) - still worked.

 

At this point I figured I'd stop while I at least had the functional footwell switch and got everything in rear hatch (motor cover and all the carpet) reassembled.   

 

Once I iron out some other issues, I may tackle the rear lock issue again, but at this point, I'm happy to NOT have to climb into the hatch from the front and use the manual cable release every time I want to get the hatch opened.

 

One final picture to close out this chapter of the story - here's my trusty sidekick who hangs out with me int he garage while working on the 968.  

 

   

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[Velocity]

For whatever reason it seems the picture with the cable hooked to the arm of the motor AND the picture of the rear lock switch were flipped vertically - they're NOT on my local machine, so not sure how to correct that.

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[Waylander]

I see you had help, we trained guide dogs for the blind for many years, and there is no dog that comes close to a Shepherd for brains and attitude

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[Roboman]

On the plane so rapid response. Didn't see spring in your pic so your switch may not reclose properly. Get your helper to hold the swith in the off position and retry the boot. Cheers

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[Velocity]

On the plane so rapid response. Didn't see spring in your pic so your switch may not reclose properly. Get your helper to hold the swith in the off position and retry the boot. Cheers

 

When you get a a place when you can elaborate more - spring in which pic?   The footwell switch, or rear hatch keyswitch?    Pretty sure I didn't lose a spring in the disassembly of the footwell switch, and never disassembled the rear hatch switch.   Think I'm at the point that I'll replace either if there are more problems with either.  :-)

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[Roboman]

Sorry velocity, plane was trundling down the runway ..... shouldn't have my phone on


The footwell switch I have has two 3mm holes in the underside of the cap. Into one of these holes fits a coil spring about the size of those in a biro/ball point pen. And on that spring is a metal cap.


Also inside the footwell switch is a "V" shaped contact curled over at each end.


When the switch is assembled the spring/cap presses onto the centre of the V-contact inside the switch, it's purpose is to ensure that when you release the switch, the V-contact which was driving your motor, flips back and completes the circuit used by the boot key switch.


If the V-contact isn't springing back you can still drive the motor from the footwell, but not from the boot key.


Another thing to look for is whether the boot release motor is "parking". When you press the footwell switch the motor should rotate and then park in the same place each time ... With the rotor arm facing towards the release cable.


Velocity I'm going to come back to this in a minute as I've just relooked at your photos and your switch may be different to mine ......


Okay, so now I'm a bit concerned I've been blabbing away and actually your switch is fine, but different to mine.


I've posted on this in a different thread "Key won't open trunk" .... You will find a wiring diagram and notes on the switches and motor, including on blowing fuses.


From the wiring diagram you can see that power leaves fuse 1 in three directions .....

a) to the left through the footwell switch when pressed, and to the motor.


b ) straight ahead through the boot lock when turned .... then through the footwell switch IF IT HAS PROPERLY RELEASED ... and on to the motor.


c) straight to the motor via an internal motor wiper..... this is the park function.


So you can see from b ) above it is critical that the footwell switch not only engages the motor when pressed, but also clicks back so the path through from the boot switch is completed.


So the quickest check you can do now is push the footwell switch off and hold it there, get someone to turn the boot key. If it works then your footwell switch isn't releasing fully, if it doesn't work then you need to get your MM and see what's correct and what's not.


I hope this helps

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