Caddy alternator dead? (Again?)

[TTait]

14 months ago I put in a reman caddy alternator with a lifetime warranty. It died in August and I had to replace it.

Now the new one appears to be dead as well:

No charging.

When I turn the key on the batt light does not come on (its a normal 194LL lamp - not LED)

When I unplug the sense wire at the alternator and jump it to ground, the batt light comes on - proving a good connection all the way to the alternator and a good batt bulb.

My only question is that the GM style plug has a red and a black wire. I have the black wire taped off and it is unused. Do I need to ground it?

Anything else to try before I rip it out again?

Tom

[DMCMW Dave]

IIRC those are odd colors - normally the two wires are red and white. White is the light wire and red needs to be connected to battery hot, either at the post right on the alternator or at the bulkhead post if you want a more accurate reference ( may get you a higher charging voltage). I'm not sure what happens if the sense wire is left unhooked but I suspect it won't work. It should most definitely not be connected to ground.

Sinces this is not the alternator we use I don't recall pin by pin which is which - do a little research and you can probably find out which is batt+ sense and which is the indicator light.

[Farrar]

Do you have one of these alternators (http://www.alternatorparts.com/cs130_sbpage2.htm)? If so, read that guide for a wiring diagram.

Farrar

[Ron]

14 months ago I put in a reman caddy alternator with a lifetime warranty. It died in August and I had to replace it.

Now the new one appears to be dead as well:

No charging.

When I turn the key on the batt light does not come on (its a normal 194LL lamp - not LED)

When I unplug the sense wire at the alternator and jump it to ground, the batt light comes on - proving a good connection all the way to the alternator and a good batt bulb.

My only question is that the GM style plug has a red and a black wire. I have the black wire taped off and it is unused. Do I need to ground it?

Anything else to try before I rip it out again?

TomIf it a caddy and "looks" like this (http://www.google.com/imgres?q=delco+7127&um=1&hl=en&sa=N&biw=1010&bih=608&tbm=isch&tbnid=czF7fEwYy_GOpM:&imgrefurl=http://www.armatureserviceco.com/ShowItem/132645%2520Universal%2520One%2520Wire%25207127-6se%2520Delco%2520Alt--reman.aspx&docid=kpryeLbHa_C81M&itg=1&imgurl=http://www.armatureserviceco.com/userdata/Images/Large/132645.jpg&w=411&h=369&ei=tqucTsXfF8nb0QGEhJDGCQ&zoom=1) the receptacle will have a "1" and "2"", or, a "R" and "F". 1 = R = (R)ectifier, 2 = F = (F)ield. If it was running for over a year, it either had a self exciter or would kick in on first rev of the engine. With the symptoms you have, you can test to see if it is the regulator or alternator (rotor or brushes....) not grounding the light's wire. Note the two small holes on the rear near the small bearing housing. The closest one is round and is for loading the brushes. The other one is a test port (usually shaped like a "D"). Just inside this hole is a tab you can ground to bypass the regulator. If you take a bare copper wire and put it into this hole to short the tab to the case and the alternator puts out, you are probably lucky and only need a regulator (depending on what shot it ,of coarse). Be careful not to go in too far as you'll hit the spinning rotor -- try it with a tooth pick while it's shut off to get the feel of it first.

[TTait]

If it a caddy and "looks" like this (http://www.google.com/imgres?q=delco+7127&um=1&hl=en&sa=N&biw=1010&bih=608&tbm=isch&tbnid=czF7fEwYy_GOpM:&imgrefurl=http://www.armatureserviceco.com/ShowItem/132645%2520Universal%2520One%2520Wire%25207127-6se%2520Delco%2520Alt--reman.aspx&docid=kpryeLbHa_C81M&itg=1&imgurl=http://www.armatureserviceco.com/userdata/Images/Large/132645.jpg&w=411&h=369&ei=tqucTsXfF8nb0QGEhJDGCQ&zoom=1) the receptacle will have a "1" and "2"", or, a "R" and "F". 1 = R = (R)ectifier, 2 = F = (F)ield. If it was running for over a year, it either had a self exciter or would kick in on first rev of the engine. With the symptoms you have, you can test to see if it is the regulator or alternator (rotor or brushes....) not grounding the light's wire. Note the two small holes on the rear near the small bearing housing. The closest one is round and is for loading the brushes. The other one is a test port (usually shaped like a "D"). Just inside this hole is a tab you can ground to bypass the regulator. If you take a bare copper wire and put it into this hole to short the tab to the case and the alternator puts out, you are probably lucky and only need a regulator (depending on what shot it ,of coarse). Be careful not to go in too far as you'll hit the spinning rotor -- try it with a tooth pick while it's shut off to get the feel of it first.


This is the one I have. I guess I'm even luckier than you thought... It has a lifetime warranty so all I have to do is pull it out and exchange it and let someone else worry about it.

So it was working with one wire, I can go and crawl under and see which one is which, but is the reason these keep dying because I need to hook up the second wire? To what?

[Farrar]

I need to hook up the second wire? To what?

Perhaps to a resistor? Some cars had them, I think -- perhaps to keep the circuit complete in case the bulb burned out. (That's just a guess as I have never worked on a GM vehicle.)

Farrar

[Ron]

This is the one I have. I guess I'm even luckier than you thought... It has a lifetime warranty so all I have to do is pull it out and exchange it and let someone else worry about it.

So it was working with one wire, I can go and crawl under and see which one is which, but is the reason these keep dying because I need to hook up the second wire? To what?

If, when the unit was 'working', you noticed that you had to rev the engine to get it to charge when first starting up, you should of had it wired as below...these work but are hard on the regulator.
1/R to the light.
2/F to 12V (Note, some connect to BAT internally. Others are jumpered to the BAT post outside the alternator, spliced to the Bat wire up the harness, or switched 12V...it don't matter much except switched helps prevent drainage in some failure instances.)
The good thing here is, UNLESS it came with a 'permanent' block-plug in the socket, you can wire it as above and it doesn't matter (ie any 1, 2, or 3 wire GM alternator in this series.)
(FYI- Some block-plugs are empty and you can use the alternator as above. Others have a resistor/diode for special apps only or rebuilder tricks to use certain regulators to get a makeshift self-energizer unit. Some have a simple jumper and you have a 50/50 chance of using it as above.)

[TTait]

I'll print that out and put it in the box with the free replacement I pick up, but at this point the caddy unit will just be a spare in case of emergency.

I've got a shiny new 'Swingle Special' coming my way, that I'm sure will make me very happy.

Thanks guys.

[TTait]

Happily, Pep Boys was dead out of the 7157, and would have to ship one in from the midwest... As the whole point was to have an off the shelf easy to get reliable replacement (and this was proving to be neither), I asked for and got the saturn unit as a free replacement instead. So Farrar, your info will come in handy after all...

The parts counter guy thought I was a freakin' moron for trying to put the saturn on in a caddy - when I explained that it was really a volvo engine in a Delorean - his head nearly exploded.

I'll run the Saturn for the weekend till the DMCMW one comes in, just to know it works right, then put it on the shelf as a ready to go tested spare - my best insurance ever for never having to put another alt in either car.


BTW - all of this started a little over a year ago when my D140 from Hervey died. If anyone has a dead Hervey alternator, its close enough to the saturn that you could give it to them as a core and then let the rebuilder figure it out...

[Farrar]

Farrar, your info will come in handy after all...

Yay! I finally helped someone! I can now die a happy man. ;-)

Farrar

[TTait]

Yay! I finally helped someone! I can now die a happy man. ;-)

Farrar


Farrar - Wait! What if I decide to go carb? You have to stay with us...

I need you man... (If Renee sees that she will totally hurl! hehe!)