1990 300E Battery/Alternator issue
 

Ok, so my car randomly started dieng one day while I was driving. I had it towed to the local dealership and they couldnt find anything wrong with it and they couldnt get it to die out. So I drove it for another week and it started dieng again. The engine doesnt go out unless the card completely stops, but all the electrical parts in the car fizzle out. (radio, Dash lights, etc) Now the only way I can start the car is by a jump. The battery is really old but alot of people have told me its the alternator. Anyone have any insight on this issue? I would appreciate any input.

Thanks,
Neralpal

1) Check (test) your batter.
2) Replace the voltage regulator in your alernator. ($30.00, a screw driver and 10 minutes of yor time)
good luck

is it just screw-in and go! What is the voltage output at:
idle and and engine off.

My 89 260e reads 14+ at idle, 13+ engine off.

Shouldn't it be 12+ for both? Case of voltage regulator?

Thanks

yes.2 screws.
idle:around 14 with daytime running light in Canada.14 is normal.
engine off:12.5 with alarm on and flashing red light(warning to would be carthief).you have to wait a while with engine off to drain off surface current(same after using charger or alternator charger),I am told.Immediately after shutting engine,my car read 12.85 or so.

Hey I have very little experience with alternators. Is there a guide anywhere to show the correct proccess on replacing a voltage regulator is it pretty simple? Just want to make sure I can handle it before i order the part. Thanks in advance.