Volks Vanagon Transporter 1986, 2.1 litre water cooled engine.

Engine will not start after 10-12 hours inactive.  Starter turns but voltage
to distributor sender unit is too low (8V when minimum is 10V), outcome is
no
fuel, no spark from control unit.  Control unit wiring checked OK.
Troubleshooting revealed a leakage of 30-40 mA from the battery with
ignition switched off and all fuses removed (maximum allowable is 3mA).  No
starting
problem with fully charged battery.
Any experience on where and how to check where this leakage origin from???

Thanks a million,

Pierre Paquette