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TOPIC: 89 SR Rear Hatch won't open!

89 SR Rear Hatch won't open! 24 Mar 2020 17:07 #21161


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I went to open the rear hatch to check the battery hold down fitting but when I pulled up on the passenger side actuation knob, all it did was buzz, indicating it was trying. The latch apparently would not release. Normally, I would hear the buzz and then the release click. After repeated buzzing attempts, it would no longer buzz. Did I blow a fuse? If I did, where on the fuse board is it located and what is its amperage? My driver's manual states that a fuse chart should be on the floorboard but it is missing and I don't have access to fuse board chart. When i purchased the car, the driver's side actuator didn't work but the passenger's did. Are they on two separate fuses? Is there an alternate way to open the hatch manually?
Last Edit: 24 Mar 2020 17:09 by whale driver. Reason: added statement
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89 SR Rear Hatch won't open! 24 Mar 2020 21:02 #21164


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With regard to my previous submission, I have concluded that it is not a fuse problem. After charging my battery several hours, I tried to open the hatch again and got the buzzing sound like before, so it is getting an electric impulse. I also tried opening the hatch with my key. The key turns but nothing happens. My only guess is a disconnect between the opening solenoid and the mechanical locking mechanism. Does the key operate the solenoid or the mechanical lock? Any other ideas? How would I open the hatch to change the solenoid if that is the case?
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89 SR Rear Hatch won't open! 27 Mar 2020 06:02 #21165


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The key should work without any electrics as it's turning a mechanical lock. You need to turn the key clockwise in the lock. If it doesn't open then put some downwards pressure on the tailgate whilst you're turning it.
'89 928 GT
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89 SR Rear Hatch won't open! 27 Mar 2020 09:02 #21166


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Finally got the hatch open. It turns out it was a combination of items. I climbed in to the trunk and removed the tool board. Discovered one of the two wires attached to the latch motor was disconnected, which is probably why the driver's side knob hadn't worked since purchase. I observed motor run with the articulating arm moving up and down, the internal spring completely compressed, but no opening click. I loosened the two bolts that hold the motor and moved the unit about a 1/4 inch down and after trying from the driver's side, "CLICK" it opened! Now I have both switches working and a lock that operates. With regard to previously using the key, even though advised it is a direct connection to the mechanical lock, that didn't work.
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89 SR Rear Hatch won't open! 29 Mar 2020 14:31 #21169


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Spent the last few days analyzing my stuck closed rear hatch problem. Was able to solve it by adjusting motor position. Now I seem to have blown a fuse, as I am absent the normal whirring sound when the switch is pulled and of course the click that accompanies opening. I need to locate the fuse and identify its exact position on the fuse panel to determine if it is now an electrical issue.  Since I am a newbie, I don't have an electrical diagram sheet or work manual.  The hatch key still won't release the lock!
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89 SR Rear Hatch won't open! 01 Apr 2020 05:35 #21170


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Is the key turning in the lock?

Here is a link to an S4 wiring diagram ... www.cardiagnostics.be/-now/PIWIS_bestand...agram%20-%201991.pdf

And the fuse / relay diagram ... www.928intl.com/repair/Relay/laterelay.htm

I printed the fuse one out and stapled it to the wooden fuse board cover.
'89 928 GT
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89 SR Rear Hatch won't open! 01 Apr 2020 14:36 #21172


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Nluk, Thanks for the diagrams. They are much needed. to answer your question: No the key will not turn in the lock as opposed to it working prior to this hatch stuck problem. Also, apparently none of my interior lights are working now. Do they operate off of a particular fuse?
Last Edit: 01 Apr 2020 15:39 by whale driver. Reason: amplifier statement
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89 SR Rear Hatch won't open! 02 Apr 2020 05:13 #21174


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Did you check fuse#25 (says for MY90-95) but check it anyway. Maybe your boot lock got changed and although the key fits it doesn't turn, or maybe the lock is seized internally? Either way you will need to remove it to check it.
'89 928 GT
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89 SR Rear Hatch won't open! 02 Apr 2020 14:15 #21176


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I want to thank all the forum members that offered advice and provided circuitry layouts. With that educational info I have finally resolved my stuck hatch failure. It was a combination of issues that had to be corrected. As I was once again not getting a whirring sound from the hatch motor, when pulling on the driver's switch, I discovered that the lead to the motor had once again disconnected. After reconnecting the lead, I still couldn't get a whirring sound. Researching the forum supplied electrical chart, I discovered that power to the motor travels via power board 7.5 amp fuse #24 (lighting) and which was blown. Evidence that the fuse was blown was indicated by lack of interior courtesy lighting. I replaced the fuse, which immediately blew and replaced it again with the same result. As a last result, I inserted a 10 amp fuse, the lights came on and I got a straining whirring sound as the motor forced the lock open! With the hatch now open, when I pulled the open switch, every thing operated normally. I could even open the mechanical lock with the key. Now the assumption was that the motor and circuitry were fine but the lock was binding. Checking how the hatch tongue entered the body latch opening, revealed that it was offset. I tried readjusting both of the lock assembly positions but the bolt holes were permanent and there was no allowance for movement. Finally, I checked the hatch side alignment and discovered, an uneven gap between the fenders and the hatch was causing the misalignment and binding. Now I just have to determine the procedure to make the hatch adjustment. Anyone that has made that adjustment have advice?
Last Edit: 04 Apr 2020 12:19 by whale driver. Reason: word correction
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Rear hatch vs body alignment procedure? 04 Apr 2020 21:57 #21177


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Now that I have my stuck rear hatch question resolved, I have to get the hatch vs left & right body gap matched. I need advise on how to access the bolts/nuts on the upper hinges without ruining the panel/upholstery? Do I have to remove the panel holding the back sun visors? What is holding that panel to the hatch (how many screws/clips)? Do I have to remove some of the headliner forward of the hatch opening?
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