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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3567
Experience:  Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes
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I just installed a new battery, into my 1991 560SEC. Prior

Customer Question

I just installed a new battery, into my 1991 560SEC.
Prior to this, all electrical in the car ran fine.
After installation - I seem to have no "unswitched" power - the seat adjustments
don't work, etc ... until and unless I start the car.
With the engine running - all is well - power to the seat adjustors, etc ...
I checked my connections - it appears that I connected everything.
Checked fuses - nothing blown, there.
Any thoughts ?
Submitted: 3 months ago.
Category: Mercedes
Expert:  Lou P. master tech replied 3 months ago.

Hello Bruce,. let me check a wiring diagram to see, what exactly do you have that does not work?

Expert:  Lou P. master tech replied 3 months ago.

we can start with fuses A and B they show to have power from the battery and also in the run position. so check those fuses for power when the key is off. then we can trace back.

Customer: replied 3 months ago.
The power seat buttons ... that was all I really checked. Usually, they will work, whether the engine is on or off, key in ignition or not, etc .... That is how it was prior to installation of new battery.
Now, with new battery - no power at all. UNTIL I start the engine - then all is operable and fine.
Not sure which fuses are A & B - I believe all fuses are numbered ...
Let me know, thanks.
Expert:  Lou P. master tech replied 3 months ago.

ok so there are letter up the side of the fuse box and number down the rows.

Expert:  Lou P. master tech replied 3 months ago.

ok sorry i was thinking of the older models, but your lettered ones are in the mix with the numbers . ill send a picture.

Expert:  Lou P. master tech replied 3 months ago.

here you go. the fuses will be good, we just need to verify power with key off and on.

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