Parasitic Battery Drain source found: Now what? Options

[Tom]

I would agree with Troy's assesment also, but there could be something else going on in the alternator. The brushes wear down coating the inside with carbon dust. If your engine is an oily one, the oil vapors and carbon dust can combine to make a" resistor". If this "resistor" happens to be across one of the diodes, it can cause a drain across it and still allow the diode to assist in the charging process.
I recently had a similar problem on my Dodge truck where it was not charging properly. Took it off to inspect and the carbon brushes were almost gone and the dust was so thick and oily that it was preventing the alt from charging correctly. Just cleaned it up, blew it out, and put in new brushes and all it back to like new.
http://www.ephotomotion.com/914engine/alt1.html
This website ahs a detailed process on what to do for your alt.
Tom

[r_towle]

in my recent experience with bosch rebuilt alternators, I would suggest you bring it up to Chelmsford auto electric and have them rebuild it for you.
Its cheaper and it will last a good long time.


Rich

[moneysmarts]

Rich:
I dropped the alt. off to Brian this morning at Chelmsford auto electric.
He just called me and said they cleaned it up, and replaced the bearings (for $65) but that the diodes were fine. They were not drawing any amps! (IMG:style_emoticons/default/blink.gif)
When I pick it up tomorrow, I'm gonna bring in my voltage regulator for him to test. But I'm reasonably sure that's not the parasite. (IMG:style_emoticons/default/WTF.gif)

[messix]

Rich:
I dropped the alt. off to Brian this morning at Chelmsford auto electric.
He just called me and said they cleaned it up, and replaced the bearings (for $65) but that the diodes were fine. They were not drawing any amps! (IMG:style_emoticons/default/blink.gif)
When I pick it up tomorrow, I'm gonna bring in my voltage regulator for him to test. But I'm reasonably sure that's not the parasite. (IMG:style_emoticons/default/WTF.gif)

how did they test this?

did they test each of the six diodes? or just check to see if it was producing a charge? it will still produce a charge if a couple of diode are shorted but will not provide full current charge. [amperage]

[moneysmarts]

I have no idea Troy.
When the guy called me and said it was ready to be picked up, I asked him if the diodes were gone. He said they checked out fine.
I told him I had a voltage leak, and described my tests, but he insisted they were ok. Just cleaned the brushes, and changed the bearing.

[r_towle]

troy, these guys are very good.
This is all they do...never ever ever had a problem.
All they do is rebuild elec motors etc...
They rewind them in house...they know what they are doing.

Rich

[messix]

I have no idea Troy.
When the guy called me and said it was ready to be picked up, I asked him if the diodes were gone. He said they checked out fine.
I told him I had a voltage leak, and described my tests, but he insisted they were ok. Just cleaned the brushes, and changed the bearing.

well then i guess you can throw it back in and see what happens.
it might be as tom says that cleaning it up will cure it.

before you pick it up i would ask them what test they do to analyze the output capacity of the alt. and if they check dc voltage ripple this will tell them if the rectifiers are bad [high ripple means bad rectifier]

[r_towle]

OK, can someone post a diagram of that little wiring section?
Alternator, starter circuit and maybe....reverse light switch?

Is that all using the same plug?

Rich

[moneysmarts]

Rich:
Just to refresh what I did...
When I pulled the 3-wire alt. plug from the relay tray, my amp draw stopped.
The I reinserted the plug, and disconnected the hot wire from the alt (attached to the starter solonoid). That also made my amp draw go away.
Should I do some other tests?

[messix]

troy, these guys are very good.
This is all they do...never ever ever had a problem.
All they do is rebuild elec motors etc...
They rewind them in house...they know what they are doing.

Rich

just wondering if they threw it on the bench and it threw out some current and assumed good to go.

[r_towle]

Rich:
Just to refresh what I did...
When I pulled the 3-wire alt. plug from the relay tray, my amp draw stopped.
The I reinserted the plug, and disconnected the hot wire from the alt (attached to the starter solonoid). That also made my amp draw go away.
Should I do some other tests?

put it back in...unplug the lead at the starter solenoid.
Also, do you have the logic circuit (looks like a relay) under the passenger seat?
Two big yellow wires (yellow and yellow with red stripe)

And , where oh where does the reverse light switch get its power from?
Seems like it may be part of that hot lead...its in the same area.
Reverse light switch gets stuck...power draw....dunno.

Rich

[messix]

Rich:
Just to refresh what I did...
When I pulled the 3-wire alt. plug from the relay tray, my amp draw stopped.
The I reinserted the plug, and disconnected the hot wire from the alt (attached to the starter solonoid). That also made my amp draw go away.
Should I do some other tests?

put it back in...unplug the lead at the starter solenoid.
Also, do you have the logic circuit (looks like a relay) under the passenger seat?
Two big yellow wires (yellow and yellow with red stripe)

And , where oh where does the reverse light switch get its power from?
Seems like it may be part of that hot lead...its in the same area.
Reverse light switch gets stuck...power draw....dunno.

Rich

reverse light is switched on the key on can't be that.

inspect the wire from the alt to the starter, could be damaged just bad enough to allow a small high resistance short, corrosion can cause high resistance shorts [draws] that when cleaned up resolve issues.

[moneysmarts]

It looks ok, but I can replace it.
Any special gauge I should use?
Braided or solid?

[SLITS]

Backup lights ... fuse 8 or 9? .... thru the main harness (pins 3 & 4 on 14 pin connector) to relay board ... thru the relay board (pins 2 & 4 on 12 pin engine harness) to engine harness which contains the two wires to switch on tranny.

[messix]

It looks ok, but I can replace it.
Any special gauge I should use?
Braided or solid?

there are no abrasions in the wire jacket? then it should be fine. the condition of the ends of the wire at the connectors, if the wire has broken strands replace the connectors.

i'm not sure what ga wire is run from the alt to the starter but 8-10 ga should be good. [prolly over kill for the short run].

how are you testing for draw? where are you doing the amp draw test at?

[messix]

Backup lights ... fuse 8 or 9? .... thru the main harness (pins 3 & 4 on 14 pin connector) to relay board ... thru the relay board (pins 2 & 4 on 12 pin engine harness) to engine harness which contains the two wires to switch on tranny.

nothing on the relay board get constant hot with the key off. the draw is not comming thru this current path.

[SLITS]

The question was "Where oh where does the backup lights get power?". No reference to the power drain.

[moneysmarts]

how are you testing for draw? where are you doing the amp draw test at?
[/quote]


I've disconnected the positive battery cable and have connected the multimeter between the battery post terminal and the cable.

[messix]

so when you diconnect the wire from the alt to the starter the draws stops, and when you pull the alt plug from the relay board the draw stops. it points to the alt as the only suspect.

[moneysmarts]

Yup.
Quirky.
I'll put it all back together tomorrow night and see what happens.
Thanks for brainstorming.