My 2005 wagon has developed a misbehavior feature (new in the last 2 weeks). It took me a while to find the sequence that makes it 100% repeatable.

If all the doors (not just some) are unlocked when I insert the key and start the engine - the tailgate glass upper section pops open immediately upon engine start.

If I lock the doors before starting, the "glass event" does not happen.

The remote release for the entire tailgate is working normally.

I seem to be having a flashback to the weird electrics of the old BL days maybe?

My local dealer has never seen this and I suspect that's generally true for all. But if you have - please tell me about it!

 

Solved.
Apparently a spontaneous programing glitch. No cause determined.

A complete "as new" reprogram of the security/locking system and it's back to normal ops.

 

oops.
Not solved.
Problem returned after just a few hours on the road.

 

It's the tailgate switch that sits under the rear wiper, the contact inside has gone. Just replace with new and your "glass event" will be fixed

For a temporary fix, just lock the door when inside car and then start the engine as you have been doing.

 

Thanks Ian,

Exactly the problem - now fixed.
USA shops just don't see enough wagons to diagnose them quickly!