Have frequent low battery on usually faithful '83 SD. Found clock was a significant current draw and that is now upplugged. Very good hint(s) on that.

Now draw is 21.1mA
with all fuses installed (fuse box near brake booster).

Removed 8A fuse #13 and
draw is 1.47mA now. Crkt #13 is the leakage path.

Fuse box label indicates loads are:
Diagnostic
Hazard Warning System
Clock (n/a as I've unplugged)
Central Locking System
Electronic Radio (I gather parenthesis around this item means "if fitted")

What is the quickest way to disconnect the radio from crkt #13?
Is there a semi-exposed lead anywhere in the cabin so I can splice in a switch.
Years ago I did the climate control R&R, and I suspect pulling the shift tray, ashtray
and then the zebrano wood panel is the way to get to the radio -- can't remember disassy well, and hoping for a quicker way to get at the radio power lead.

My memory is hazy on this but it's something like - remove astray, remove 2 screws keeping ashtray frame in console (watch the screws because they'll fall into an abyss), reach in and pull out radio. If it's the factory radio, it might need a code or a trip to the dealer to reset after disconnecting the power wires. The power wires (+12V constant and +12V switched) are in a 4-pin connector distinct from the speaker connectors.

It'll be easier to first disconnect the central locking pump. It's to the right of the spare tire wrapped in a foam case. It might be cycling continuously

Sixto
87 300D

The factory spec is 10 mA or less so if you're below 2 mA there shouldn't be any need to push farther. Sixto's note on the central locking pump is valid. It's so quiet that you are unlikely to hear it running and, if it sticks "ON" after you close and lock the doors, it could run all day and you would never know. When you come back to a dead battery the pump will have tripped off and you will find nothing wrong.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Also try disconnecting the antennae motor. monitor for results.

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD