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300sd 1982: Electric surge under console drains battery

Submitted by sez2002 on 23 June 2010 - 1:16pm.

Dear Friends!
I am an owner of MB 300SD 1982. Recently, the car presents disabling electrical issue which I hope to pin point eventually. There is a electrical surge somewhere under console ( I can hear climate control clicking) which drains all electric charge (battery). When it happens all my dashboard indicators go wild. Surprisangly, all fuses stay intact. I suspect it may be blower engine goes bad, but I am not sure. Anybody had this problem before?

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Suspect voltage regulator

23 June 2010 - 3:00pm
Kent Bergsma

 This could be symptomatic of a bad voltage regulator.  You could have your alternator output tested or just replace the regulator and see what happens.

Here is the link to the part CLICK HERE

Bingo!

15 July 2010 - 6:47am
sez2002

Thank you, Kent!

You were right about the regulator. My mechanic replaced it together with damaged alternator and battery (thanks G-d on warranty). Also the alternator housing was cracked causing alternator to shake - changed as well. Now, the cars starts and all electric accessories work fine. Now I can focus on the rust.

Back to the shop - the battery doesn't get charged

27 July 2010 - 4:11pm
sez2002

dear Kent,

I hope you'll read this. After a week of running, my MB didn't start again. I took it back to the mechanic. As it turned out new alternator puts out 14V, but only 10V reached the battery. We are braking our heads what could it be? New voltage regulator needs adjustment?

Thank You,
Sergey

No adjustment available

28 July 2010 - 9:28am
Kent Bergsma

The regulator can't be adjusted. Did your mechanic install an aftermarket alternator and regulator? New regulators can fail so I would start by trying a replacement regulator. Are are sure ALL you cable contacts are clean and tight - including the grounding cable from the engine to the firewall?

I'll take your advise to the shop

29 July 2010 - 9:26am
sez2002

Thank You, Kent!

I just printed your advise and I will take it to the shop. I will come back to you with the result.

With Blessings,
Sergey

Fixed!

30 July 2010 - 9:43am
sez2002

Dear Kent,

The mechanic obtained brand new alteranator and regulator directly from MB dealer; all battery and alternator wiring including one you've mentioned were changed. Result: 13V on the battery with lights and AC running,

Thank you,
Sergey