Boy, is there a straightforward replacement for the whole hatch release system that anyone has ever developed? I tried setting up a solenoid driven back-up system but it never worked properly and I finally removed it. It would be very cool to have two small powerful solenoids which could be mounted adjacent to each latching mechanism which would pull the slide open and release the hatch. I tried using two center-mounted solenoids and ran sheathed bicycle cables to the latches (which were modified to accept a second cable). It "sort of" worked but then would fail. The solenoids triggered but the amount of flex for the relatively long cables just did not prove adequate. I think the idea would work if you could locate solenoids in line with the latches and used a relatively short and direct cable connection. But, I've never located and appropriately powerful solenoid or figured out how to unobtrusively mount it.
Right before I had to sell my former car many years ago this was the last topic of discussion between a small group that never got resolved.
As far as the emergency release I came came up with an idea to mount something like this behind the license plate.
Prime-Line Brushed Chrome Emergency Release Lock Kit-GD 52143 at The Home Depot
This type of release is used in detached garages without standard door access. During a power failure a key is used and the lock comes out with a steel cable which is attached to the release mechanism of the garage door opener.
Like mieczkow, We ran across the not being able to source powerful enough solenoids also so we were going in the direction of using electric window or worm drive motors as they would provide enough torque to trigger the release.
Also in talks at the time was coming up with a way to replace the short section of cable between the two rear latches with a solid rod.
When the topic of the solid rod came up I also mentioned that the majority of cars have direct key access to the trunk or hatch and if going to a solid rod it would be fairly easy to attach the rod ends to a cam of a key lock.
Someone had mentioned pneumatic and/or hydraulic actuators like someone on this current thread but decided that we had our hands full keeping what we already have from leaking and did not want to add other items to the car with that potential.
I wish I could move forward on these but at this time all my efforts must go towards getting my car operational.
