I've done a search on Alternator issues, diode issues, parasitic drain issues, and the many anomalies others seem to have, but my one question here about the readings I'm getting for the Diode mode test does not seem to have been covered as specific as I would like to be with my question. I've itemized all the conditions and tests I've done, and then note my last two bullet points about the diode testing readings - I'm quite sure that's the problem, but as always, would like a second opinion.

My Crossfire SRT-6 is eating the battery when parked, overnight, one day. Nothing was left on, charged the battery, did it again. Quite sure it's a diode(s) in the Altenator, but that's quite surprising considering the car has only 36,000 miles on it.This suddenly started happening, there was no prior indications or recurring charging/engine idle, I have had no electronics/lighting acting wonky. No warning lights on the dash while running about the battery or charging.

Nothing is wrong with the battery, it's only a year old. The battery charges fine with a charger and holds a charge. I have both an old Sears Die-Hard 10-AMP charger with engine start for 'lead-acid bath' regular batteries, and an Optimate 6 Ampmatic Charger for AGM/Gel batteries. Just to be sure, I tested with another new battery I have. Both batteries test Voltage at 12.64 / 12.62 - so good on both counts.

All connections are good - California car, no corrosion or cracked wires, looks like new under the hood, never sees rain. Car is all stock as it left the showroom, except for a radio that was professionally installed years ago and a Sprintbooster installed - neither have any shorts or issues.

There is no parasitic drain or overloading draw/short circuits - that test reads at .024 . - (typographical error corrected)

Charging test with everything on (headlights/Air Conditioning /Dome Light): reads 14.42v / 14.45v

My multimeter is working fine/tests good, no issues.

HOWEVER - when I do the alternator Diode test, car off, and multimeter set as in the photos, I get the following:

With the black lead on the positive post / red lead on the alternator housing I get 205 as shown. (.205 volts)

With the red lead on the positive post and black lead on the alternator housing, it climbs through the range to max at '1.484 / 1.494' as shown.

I have not done an AC multimeter test on the alternator yet, merely ran out of time today, had another project to tackle elsewhere. But with the above result of 205 (.205 volts) as opposed to a range of 500 to 800 (0.5 to 0.8 volts), wouldn't one deduce that's suspect considering all else is working properly, especially with the battery draining in a single night?





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