Electrical Drain??

[metalmonkey47]

So I've been chasing this phantom electrical drain in my B310.

 

To start, I pulled all the fuses and still had the drain. I disconnected the signal wire from the back of the alternator and the drain ceased. I pulled the alternator and too it to autozone to have it tested and it came back 100%.

 

I didn't find any short on the harness anywhere. If it stays hooked up, I come back out in the morning and the batteries dead.

 

Any ideas?

[Icehouse]

It has to be bad diodes in the alt. there is nothing else it could be. Have you tried Hainz's trick? Hook a test light inbetween the negative battery post and the negative cable (with the negative disconnected using the test light to complete the circuit) if there is a short it will light up, then pull fuses (which you have done) then you can start unhooking other items.

[banzai510(hainz)]

put all the fuses back in . Ck for drain. if still have a drain then disconnect the wire to alternator. if drain goes away, get another alternator.

[metalmonkey47]

I've pulled everything possible. All fuses disconnected and such.

 

I had the alternator tested and when I pulled it I found a sticker indicating it had been replaced prior to me buying the car. Autozone ran it on their machine and the diode test came back OK, which is what I thought it might be in the first place.

 

The drain is approximately 8.8ma

[banzai510(hainz)]

I did a ck on BigDaves 521 truck and I disconnected the alternator and the drain went away.It had a dead battery thus killed the battery.Battery was bad needed a new battery also.

 

I will assume this is the same.Not the battery prolem but the drain

Maybe go to NAPA and have them test it. Load ck it also.

 

So I thinks its the alternator. You disconnected all the fuses. The alternator WIRE is hooked up to the battery via the fusable link.The alternator case is grounded so something in alternator is doing it. But remember Im not a 310expert.

 

Maybe you can ck the alternator output to the case on the resistance scale of your ohm meter. 12v/8.8ma= 1363 ohms or close to it.

or if you digital volt meter has a diode cker try that put leads both ways.

 

Maybe take a volt meter/ohm meter to store and ck a new one this way to compare readings

[datsunaholic]

Generally if the diodes short (any of the 3) then it will light the Alternator light when the engine is off. But not always, AND if the diodes were shorted it'd still drain even if the 2-prong plug was unplugged (would just turn off the light).

 

The alternator circuit feeds the choke relay, so it's possible the diodes are OK but something else is wrong in the alternator that's backfeeding the system.

 

Remember, though, that the Autozone (and any parts store) alternator tester is designed to work with many different types of alternators, and if ANY of the settings are wrong on the tester it can give false readings positive or negative. I had an alternator that tested OK in 3 different Schucks stores and they wouldn't replace it (warranty) but never worked in the car... I tried 2 cars, the problem always followed the alternator and the other car's alternator worked in both cars. Finally found a Schucks that their testing machine was broke and they replaced it. Those "Lifetime" alternators really sucked, especially the "MTA" brand ones they used in the early mid 90s. 50% DOA rate, and of the ones that did work at first most died within a year.

[banzai510(hainz)]

The alternator circuit feeds the choke relay, so it's possible the diodes are OK but something else is wrong in the alternator that's backfeeding the system.

 

Fuck forgot about that one, I guess you could disconnect that relay or the wire to the choke.

[yello620]

An ignition switch that is failing can also cause this same problem, or a switch that has had a lubricant put in it. Your ignition switch also has battery power all the time.

 

I chased this same problem many years ago in a 620. Had the hardest time finding the problem cause pulling all the fuses didnt to the trick. Pulled the wire connector off the back of the ignition key switch and my drain stopped(using the test light on the negative terminal trick). Realized(didnt know any better either) that i had put a graphite compound in the key switch because the key was getting sticky. The graphite i used was a conductor that created a short in the wiring.

 

Good Luck