Hey all,
Over the past year i have been fixing up a 91 LS that i rescued from its 7 year garden grave. It has devoured 2 batteries. I checked alternator and it was charging good but discovered a parasitic drain. After much frustration I narrowed it down to that stupid bumper on brake peddle being missing. Fixed that and no more drain. Then the ECM fried from water so I had to replace that and fix cowl. Now the car is dry and water proof again. Now as of yesterday a massive battery drain is back and the battery is fried. The alternator is putting out 16.5V at idle and the battery drain stops when I disconnect the alt. in wire from under hood fuse box.

My questions are these. First, is the voltage regulator internal or external? All the replacement alternators I have looked at say internal but that finned silver box on drivers strut tower is labeled at voltage regulator. Second. Is my overcharge issue a result of the alternator or that separate "voltage regulator"? Any tests I can perform to confirm?

Thank you!

 

That's the injector resistor, not a voltage regulator.

Your alternator has an internal voltage regulator.

If disconnecting the alternator connectors cures the drain, then the alternator is shorted internally.

 

Ditto the above^^^, the voltage regulator in the alt. is toast, 16.5V is way too high, should be more like 14.5V. 94

 

thanks all.