Tailgate won't unlock

I have a 1992 525i Touring (sorry, don't know the 'E' number).
When I unlock the doors the tailgate remains locked. The window part of the tailgate opens OK but I can't expect the dog to jump in through
that!
It's happened before and then worked again after a couple of days so I'm guessing it's a sticky solenoid or something.
Can anyone give a me a clue as to where to start looking?
Thanks
Andy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Andy wrote:

You have an E34. In fact, you have the same year and make I do.
Wikipedia has an excellent chart of the E numbers at http://en.wikipedia.org/wiki/BMW_E34

Are you saying your dog is as old as the car?

It is an electronic problem, as explained to me by a repair shop last week. I've asked for an estimate to repair the problem.
The experience I've had is similar to yours. There is no problem whatsoever with getting the window to release--pressing the button gets an immediate response. (Unfortunately, my window will not stay in the up position, so it's not much good to me except for putting small items into the cargo area.)
Until I talked to my mechanic, I always thought that I had to unlock the rear gate, but he showed me that holding the door button for several seconds will get the tailgate to open. It takes, on average, about 5 seconds for the door to open, but indeed, it does.
The quick solution is open the tailgate manually--put the key in and it unlocks instantly. (Look on the bright side and call this 60s retro.)

I'm sorry I don't know how to fix it myself.
-- Michael Poplawski Victoria, BC Canada
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

expected!
Thanks for the advice Michael.
The tailgate lock is stiff as old harry, having never been used, but a squirt of WD40 got it working and once the tailgate was open it now works with the central locking again. Methinks it needs some lubrication somewhere.
Andy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.