A competent auto electrician can work from a schematic if it's available.

Function of fuse 8 on fuse holder B -SB8- 15A -Rear lid control unit-J605- Top Fuses /Centre Dash.
Rear lid lock motor has a violet colored wire, you could check for power on that.
Rear lid contact switch goes back to J519 Onboard supply control unit, brown/blue, brown/black, (could be neg. potential -take care)
Also - if it has "SAFELOCK" function could be worth considering.
As always - do not allow 12v onto just any wires, risk of Control Units damage,
BE CAREFUL PROBING. If not familiar with electrical systems, best to find someone who is, and specifically T5 VW.