Anyone have tips for troubleshooting key-off load on my 87 560SL?

Current draw is about .72 amps when the car is not running...resulting in a drained battery when the car sits for a day or two. I take it that value is higher than it should be.

I have narrowed the draw to the "always hot" circuit 30...fuse 12 on the fuse panel.

Obviously I can pull the plug on the antenna. No I don't have any lights on.

What connectors can I pull to check:

- trunk/dome lights
- hazard lights/turn signals
- alarm system
- central locking
- radio
- "warning system"
- clock

What is the easiest way to check this circuit?

best,

Dave

That is quite a bit of current draw, I had a 89 Sl that had a pinched wire going to the trunk light, back feeding thru high mounted stop lamp thru the brake light circuit. It was tough to get to because of the trunk hinge arm. You just have to chase those circuits, once narrowed to a fuse, pull all the consumers untill it goes away. The clock, radio, alarm, are probably out but as I recall there are other items. I noticed a faint glow in a dark garage from the tail and high mounted light.

Peter I saw that when I did a search before posting and believe me it will be the first thing I check when I get back to working on the car tonight!

Thanks,

Dave

Based on experience with several cars, I'd start by removing the trunk light bulb to see if that removes your key-off load.

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)

Trunk bulb already removed. I did a cursory inspection of the trunk lid wiring and didn't find anything, though I'd like to get a better look at the end near the hinges. What is the easiest way to access that end? Is there a connector somwhere that can be unplugged for that circuit or is it part of the main harness?

thanks,

Dave

The problem is there is no connector that I found, and when it was "chafed" it is in a braid so it was hard to tell. It is probably shorted before the bulb so if it is removed the draw is still there. It wont be a short to ground otherwise the fuse would blow it is going thru something like another bulb!
I know how miserable the area is, the panel comes off but it is a real pain since you have to peel off the rug to get at the screws. It still is not a gurantee that the problem lies there. Does the 87 have a high mounted stop lamp, otherwise all my opinions are off since there are only two wires to the trunk lamp, and I dont know if there is an alarm circuit there

87 does have the high mount stop lamp.

I wish the service manual had a better illustration of the wiring harness layout...

best,

Dave

Victory.

"Courtesy Lamps" shorting to the windshield header. That's "dome lamps" in American.

I've had problems with those before, blowing fuse 12...

Hopefully I've repositioned the connectors/wiring enough to avoid these problems in the future. For now I'm back down to 16mA or whatever for key-off load.

Is it just me or do the 5w & 10w interior bulbs fail at a high rate. Seems like I'm always finding another one that is out. This time it was passenger footwell.

FWIW there is a connector - X18 - that supposedly goes to the rear lights/trunk light/antenna etc. The service manual graphics are SO BAD I'm still wondering where it is. All I know is "behind glove box...X18 (above)"...

Thanks again for the help,

Dave
87 560sl