Hi, havin a strange prob with my 94 22re runner.
Died on the wife a couple weeks ago. She said it lacked power, gauges stopped working then died and wouldn't turn over. Sounded like the alt pooped out to me. Grabbed a new battery to get her home. Once had it in the garage I checked volts and the alt is puttin out 14.6ish, ok? Decided to let it ride but now havin the same situation again. Tested again and found that the voltage slowly drops at the battery when the air condition is on. Ran the ac for 30min or so and saw volts fall to 12.6 from 14.6. Had the alternator tested and looks fine. I'm lost.
Any help is greatly appreciated.

 

Welcome !!

Your checking the alternator output with as much electrical load as possible on??

Did you take notice if the engine is idling up when the compressor pulls in??

Engine rpm slows down alternator output drops

With all the other electrical accessories the load might be just to much for the stock alternator.

Has the wire from the B terminal of the alternator to the fuse block ever been replaced.

They tend to get old and brittle

The AC compressor puts a load on the engine.

The electrical load is just the clutch and blower motor

 

I did the volt test with as much load as i could yes. This is the little lady's ride so have to test with all accessories load potential High beams on, ac, stereo and interior lights. Voltage was good until i turned the ac on. Ac clutch kicks in and out normally, engine idles up and volts increase. Turn ac off and volts increase. did these test over about 1hr idling in the driveway cause it is a slow drain down. Short trips to town on cool days are fine, now running errands all over town on hot days she gets the battery light but has yet to die on her.
All wiring is original. I'll test the B terminal. Elect system has been fine for years so would expect the alt to be sufficient.
Thanks so much for the help!

 

B terminal tests good. .1 volt drop from alt to bat. Think that's ok?
Volts appear to drop when ac clutch is DISengaged.
Clutch engages engine idles up volts increase. Clutch lets off volts drop. Makes sense cause engine idles down but... If left to idle, over time the battery drains to 12.5ish volts. I have stopped my test there because I don't want to wreck the new bat.
Could the ac clutch be bad and drawing while disengaged?