It isnt the switch, it's the security module in the trunk.

And the only way to find what is draining a battery, is to insert an ammeter in the battery ground lead and do this;

• Close doors and trunklid
• Make sure key is NOT in the ignition
• Make sure dome light times out
• Wait three minutes
• NOW, what is the current flowing? Anything over .055amp (55 milliamp) is out of tolerance.

IF you see too much current, start pulling fuses until the current drops to where it should be - the last fuse pulled is the clue.
If you see NO currrent, you have the meter setup incorrectly or you have a blown fuse in the meter.