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1990 Mercedes Benz SL300 Repair Question


Topics covered: Fuse, Battery, Radio.
Mileage: No information provided.

Asked on December 13, 2009

1990 Mercedes Benz SL300 Battery discharge

Electrical problem
1990 Mercedes Benz SL300 6 cyl Two Wheel Drive Automatic 93000 miles

I have a 1990 SL300 that the battery goes dead after a day. The car is usually stored in a heated area but now its in an unheated garage. This problem just seemed to start when we had our fisrt real freezeing temps.
I hooked a Snap-On graphic meter between the battery. Bypassed the trunk light and the meter read a 0.110 amp draw. I have done the following tasks without finding the problem or reducing the draw. Removed fuses and fuseable links in 3 fuse boxes one at a time. Disconnected the alternator. Removed the aftermarket radio. Car is completly original and well maintained. The exception is that an aftermarket radio was installed a couple of years ago.
Could there be a stuck relay?
Is there a fuse or fuseable link not located in the 3 boxes?
Backfeed from one circuuit to another?
Is there a timer icircuit that is not shuting down?
Any ideas would be helpful.
Thanks
Avatar Asked by Humvee

Answer

Replied on December 14, 2009

wow, you have tried everything that I would have suggested that a normal person with a limited tool box to do.

the next thing to do is start tracing every circuit after you print out the schematics.

Tiny Answered by buddycraigg (expert)
2,499 answers provided
Replied on December 14, 2009

I guess it's time to start pulling the dash.....thanks

Tiny Response from Humvee
1 question asked
Replied on December 15, 2009

I tried looking at the schematics for any hidden fuses or links, but my on-line program has chopped the manual up so bad that I couldn't follow the pages.

Do you have a manual with a good wiring diagram in it?

Tiny Answered by buddycraigg (expert)
2,499 answers provided

Replied on December 16, 2009

Mine are also in about 20 sections/groups. At least they are not in German.

Tiny Response from Humvee
1 question asked