Well, since it was my car and I have fixed it, I have the answer to the puzzle.

I bought a rebuilt alternator and put it in, and that fixed the issue. It is externally regulated, so the regulator is even the same.

so, since this car had the battery put in with the polarity reversed & people trying to get it to start that way, my guess is something fried and shorts when the key is off...

Definitely something inside the alternator though, and not the regulator.

The remaining "genius wire" issues are that the dash lights and horn don't work and he has the electric radiator supplementary fan hooked up to some sort of toggle switch and indicator light between the window switches, so I have to make sure the thermo time switch & any other OE stuffs needed are still in the circuit. I like automatic stuff, having to remember to flip a toggle is not my preference.

Ran across another MBZ at a yard all full of genius wires, immobilizers, amplifiers, speakers, brackets and switches. what is it with these cars and the wanna-be electrical engineers? I thought "vw rabbit diesel guy" was bad with the wires, but these "genius wire" guys are diabolical!

take care,

Jester

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Current MBZ:
1970 280s - no rust california car
1966 230s - Dad's merc. big honkin sunroof, in family since early 80's

Departed MBZ:
1986 300sd - Mom's killed by a wreck @ 200k or so
1976 W123 300d - Slow, sold due to rust @ 275k mi
1970 280SE - Bought new, my first car in 1986. died from rust @ 300k, ran like a top.
196? 230 - My brother's college car. Rusted to pieces & egnine put in 230s we still have.

Note to those pondering which alternator to use in their 250, 280 etc... When I got my '72 250 in 1988, I replaced the dead alternator/separate regulator with a later-type spare 55 amp/integral-regulator alternator that my dad had on a shelf in his garage. The mounting on that alternator was different so I swapped the front half of the alternator cases to be able to use the replacemnt in my car. About ten years later, that one died and it turned out an OE separate regulator and alternator replacement was cheaper to buy than the integral unit, so I changed it back to the OE setup. The integral and separate-regulator units will interchange. Simply leave the regulator harness disconnected as the integral-regulator unit won't have the socket for it anyway. However, you may need to swap the mounting half of the case in order to substitute a later or higher wattage alternator.

Happy Motoring, Mark

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DrDKW

When you grease the car, don't forget the driveshaft and the two fittings on the rear swing axle joint.

Too bad about the faulty rewiring. I would think that the alternator diodes are bad after being hooked up backwards.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.