2002 Jetta starting/electrical issue

Here is the run down:

2002 Jetta-V6-TipTronic-“Hecho en Mexico”

Car will not start unless jumped. Not completely dead (like an alternator problem) but just the signs of a dead battery (clicking). Once jumped, is fine, until it sits overnight.

Had the battery replaced twice within the past 2 months (DieHard-International).

Alternator checked fine (had it replaced about 6 months ago w/ a refurbished one).

Took to dealership three times and they had it for a total of about two weeks. The first time, they found a major draw from the radio. They disconnected the radio but the same issue. Took it back twice since then. Checked newest battery, fine. Checked alternator, fine. The last time they stated that there was a half amp draw but could not isolate where it was coming from. They also stated it sat for two days (w/ doors unlocked & windows down) then cranked fine on the third. Took it home, cranked it the next morning and no go. They asked me to not jump it and have it towed to them so they could better isolate the draw. Not too confident they can/will find it.

Any suggestions?

A half ampere is way too much of a current draw. The service shop is going to have to pull fuses until this draw disappears. Once the circuit is isolated, the units powered by this circuit should be inspected and disconnected to narrow the faulty component. From your post it has to be something that was not done at the shop when they let it sit two days, like remote lock, alarm arm, alarm itself, etc. Maybe something special about the way you park your car.