My Voltage Regulator was replaced and now my battery drains. There is a loose short black wire on top of the alternator in the center mid-right of the attached picture. The wire is wrapped in electrical tape, but since it partially unwrapped it looks like a black flag; the black wire is at a 90 degree angle to the red wire. I am looking for a diagram of alternator wiring.

A battery test showed the voltage regulator failed, diodes and alternator were okay. Since VR was replaced O'Reilly Auto said there could be an electrical issue.

The fuse that powers locks & trunk light showed a drain but after it was removed the battery still drains. I never had a glove box light and there is nothing else I can think of that may be significant except perhaps that the seat belt light sometimes dings when I am driving and my belt is on. TU

 

should be three wires on the alternator. heavy red one to B+ comes from the battery by way of the starter motor. thinner red one to D+ comes from the dashboard alternator light, and bootstraps the alternator. blue wire is ground.

the bundle that includes the D+ and ground wire also has a wire to the oil pressure sensor on the exhaust side of the engine block, near the oil filter. my diagrams indicate this wire is black.

 

oh, as far as leak trouble shooting.

first thing I'd do is get a digital multi meter that has a 10 amp range. usually you move the red + lead from the regular socket to a different socket for this mode AND flip the switch to 'amps'. amp meters are different than volt meters, you NEVER EVER put them across a voltage like a battery, instead, you put them in SERIES with a load. disconnect the positive battery terminal, connect the red + lead to the battery post, and the black - lead to the cable terminal to measure the leakaga current.... its probably less than 1 amp. note you might see an initially higher value as various electronic circuits filter capacitors recharge themselves, wait the few seconds it takes to get a steady reading.

if you measure leakage much over 0.010 amp (aka 10 milliamps), then something likely is wrong. there's 3-4 smaller red wires attached to the big red starter/alternator wire. separate these, and do this same test with each wire one at a time, to see if the drain is on the main fat lead (which goes to the starter and alternator) or one of the auxilliary wires (on a 240, one goes to the 25A fuse to the fuel injection, and another goes to the 'positive terminal', and another might go to the headlight relay).

if you've isolated it to the positive terminal wire, then try removing each fuse below the driver dash one at a time, repeating the amp meter test. if you narrow it down to a fuse (eg, if you remove fuse X the drain current goes away), then you've found it.

ALWAYS PUT THE METER BACK IN REGULAR VOLT MODE after using it as an amp meter.. an amp meter is a dead short if you put it across a voltage, and you'll likely blow a 10amp fuse thats inside the meter.

 

Will try, TU