current leak in a 2008 SAN 230
 

Please electric guru can you help me!
I have a blue sea perko and ACR .One AGM battery only for music and one classic battery for starter and every thing else - all the battery are nearly new
When the perko switch is off no problems
When the perko switch is on no problems on AGM but the other battery will be drained in one day
How to find the leak?