Battery Drain problem

[vanharlin]

I have a battery drain problem. I have installed a new battery, a new alternator with 0 results. I have found if I leave the alternator plug disconnected there is no drain. With everything connected, everything works properly, alternator charges as it should, all lights work properly including instrument panel. Its a 2002 Montecarlo. Any Ideas. Thanks.

[aleekat]

http://www.aa1car.com/library/battery_runs_down.htm

[j cAT]

Originally Posted by vanharlin

I have a battery drain problem. I have installed a new battery, a new alternator with 0 results. I have found if I leave the alternator plug disconnected there is no drain. With everything connected, everything works properly, alternator charges as it should, all lights work properly including instrument panel. Its a 2002 Montecarlo. Any Ideas. Thanks.

with the alternator wire disconnected and the issue is gone , then the alternator is defective. you say new alternator , is it new to the vehicle or new like never used before ?

rebuilt is not new and not recommended.

[vanharlin]

Brand new $170.00 alternator, not rebuilt. Results are the same as with the old original alternator. I can leave the positive wire to the alternator connected but leave the wire plug to the alternator disconnected and there is no drain. Something downstream of the alternator plug is shorted or stuck like the old regulators used to do. I,m old school mechanics and not versed in modules, chips etc, and no wiring diagrahm. Thank you for inquiring. Any help is greatly appreciated. Aleekat,s information was good. The web site he gave me suggested to pull fuses and such while monitoring the drain, however, I,m a little leery to do that just yet since like I say, I,m old school mechanics and don't know what else I might damage. It may come to that. I've checked wiring harness and don't see any apparent damage anywhere. With everything hooked up, there is no alarms, no check engine lights and the vehicle runs like it should. I've pulled the bulb in the trunk and monitored all other lights and found nothing staying on.

[Tech II]

There are only two wires in that connector.....one to a fuse, and the other to the PCM......so if this is a new alternator, and it's ok, then I'm leaning towards a PCM.....

But I would like to see an ampmeter on the battery, to see exactly what that draw is.......normally should be under 30 ma, or 0.030 amps.....you disconnect the Negative cable from the battery, and insert the ampmeter in series between the battery (-) terminal and the negative cable......then wait about 15-20 minutes, to give all modules a chance to go to sleep....then, the reading should be at it's lowest...

[j cAT]

Originally Posted by vanharlin

Brand new $170.00 alternator, not rebuilt. Results are the same as with the old original alternator. I can leave the positive wire to the alternator connected but leave the wire plug to the alternator disconnected and there is no drain. Something downstream of the alternator plug is shorted or stuck like the old regulators used to do. I,m old school mechanics and not versed in modules, chips etc, and no wiring diagrahm. Thank you for inquiring. Any help is greatly appreciated. Aleekat,s information was good. The web site he gave me suggested to pull fuses and such while monitoring the drain, however, I,m a little leery to do that just yet since like I say, I,m old school mechanics and don't know what else I might damage. It may come to that. I've checked wiring harness and don't see any apparent damage anywhere. With everything hooked up, there is no alarms, no check engine lights and the vehicle runs like it should. I've pulled the bulb in the trunk and monitored all other lights and found nothing staying on.

with the key in the off position check that you have no voltage at the small connector wires going to the rear of the alternator[ remove connector]. when the ignition is off you should have no voltage on those wires. if power is there then the field of the alternator is sucking down the battery . the only time volts should be on those wires is when the ignition is on.

I would have the old alternator checked out also .

the f wire is to the field. the regulator is all inside. the other wire is the dash indicator. with the key off there should be no connection to the battery in these circuits. no if the alternator is messed up then this is also possible

you did not have to change the connector ? some do so it will work when not made for the correct vehicle.

[vanharlin]

Originally Posted by Tech II

There are only two wires in that connector.....one to a fuse, and the other to the PCM......so if this is a new alternator, and it's ok, then I'm leaning towards a PCM.....

But I would like to see an ampmeter on the battery, to see exactly what that draw is.......normally should be under 30 ma, or 0.030 amps.....you disconnect the Negative cable from the battery, and insert the ampmeter in series between the battery (-) terminal and the negative cable......then wait about 15-20 minutes, to give all modules a chance to go to sleep....then, the reading should be at it's lowest...

Could not get a ma reading, don't know why, but did get a 1.77 amp draw with both, the alt plugged in and unplugged. Hooked everything back up, started the car and have ABS and Trac Off alarms, this is new. Now, the amp draw is 8.79 amps and have to totally disconnect alt to get the draw back to the 1.77 amps. Alt is putting out 13.8 volts but ABS and Trac Off alarms will not clear. After giving the car a few minutes, amp draw went back to 1.77 amps. Guess all modules weren,t asleep yet

[vanharlin]

Originally Posted by j cAT

with the key in the off position check that you have no voltage at the small connector wires going to the rear of the alternator[ remove connector]. when the ignition is off you should have no voltage on those wires. if power is there then the field of the alternator is sucking down the battery . the only time volts should be on those wires is when the ignition is on.

I would have the old alternator checked out also .

the f wire is to the field. the regulator is all inside. the other wire is the dash indicator. with the key off there should be no connection to the battery in these circuits. no if the alternator is messed up then this is also possible

you did not have to change the connector ? some do so it will work when not made for the correct vehicle.

This is a two wire plug. It is on top of the alternator, not on the back. Unplugged from the alternator, key off, there is 12 volts to one of the wires. Did not change the plug, all original. I have no way to check with it plugged up.

[Tech II]

According to my schematics, the orange wire going to the alternator harness should be hot at all times.....

Since you have a 1.77 amp draw(that is 1770 ma) with the alternator disconnected, the problem is not the alternator....

Do you have any accessories added to the vehicle?

With almost a 2 amp draw, no wonder your battery dies....

Unfortunately, the only way to have a chance at finding the circuit that's at fault, it to make sure EVERYTHING IS OFF, attach your ampmeter, and when you read 1.77 amps, start pulling a fuse one at a time until you see the reading drop to an acceptable 30 ma.....

[j cAT]

Originally Posted by vanharlin

This is a two wire plug. It is on top of the alternator, not on the back. Unplugged from the alternator, key off, there is 12 volts to one of the wires. Did not change the plug, all original. I have no way to check with it plugged up.

sorry about the info I gave you was from the wrong diagram. the alternator plug does go into the rear of the alternator which is opposite of the pulley. the connector is mounted into the rear of the plastic cover on top so it is accessible . this is the location of the regulator under the plastic cover in the rear .

the connector has 4 pins . pin D is the orange wire which has 12 volts to it at all times . pin L which is red is from the PCM this turns the alternator on and also will go to the dash indicator.

It is possible that the PCM is commanding the alternator on when you shutdown the vehicle. I still think that the alternator { regulator} is the problem.

see if you get a voltage at the pin L red wire if not then I would guess its the alternator. if you do get a voltage at pin L with the connector disconnected then the PCM could be bad.

[vanharlin]

Originally Posted by Tech II

According to my schematics, the orange wire going to the alternator harness should be hot at all times.....

Since you have a 1.77 amp draw(that is 1770 ma) with the alternator disconnected, the problem is not the alternator....

Do you have any accessories added to the vehicle?

With almost a 2 amp draw, no wonder your battery dies....

Unfortunately, the only way to have a chance at finding the circuit that's at fault, it to make sure EVERYTHING IS OFF, attach your ampmeter, and when you read 1.77 amps, start pulling a fuse one at a time until you see the reading drop to an acceptable 30 ma.....

I think I need to clarify that I have a 1.77 amp draw with or without the alt hooked up, however, the battery only goes down if the alt is hooked up. With alt unplugged the battery will maintain charge. Plulled all fuses in both upper and lower fuse blocks (underhood) today. Left I/P fuse (big 60 fuse)described in owners manual as left fuse (Battery) in upper block, dropped draw to 1.2 amps however killed everything in the car. RT I/P #3 fuse described as defogger & Audio system in lower block dropped draw to .57 amps. Its also a big 60 fuse. No other changes. Will leave the RT I/P #3 fuse out over night and see what happens. Thanks so much for your help. I,ll let you know the results.

[vanharlin]

Originally Posted by j cAT

sorry about the info I gave you was from the wrong diagram. the alternator plug does go into the rear of the alternator which is opposite of the pulley. the connector is mounted into the rear of the plastic cover on top so it is accessible . this is the location of the regulator under the plastic cover in the rear .

the connector has 4 pins . pin D is the orange wire which has 12 volts to it at all times . pin L which is red is from the PCM this turns the alternator on and also will go to the dash indicator.

It is possible that the PCM is commanding the alternator on when you shutdown the vehicle. I still think that the alternator { regulator} is the problem.

see if you get a voltage at the pin L red wire if not then I would guess its the alternator. if you do get a voltage at pin L with the connector disconnected then the PCM could be bad.

You're correct. Pin D has full voltage but Pin L has none but Pin D has about .5 volts with battery ground cable disconnected. Could that just be backfeed? Being old school, I lean toward the alt also but why is the battery drain the same regardless if the alt is hooked up or not and at the same time, the battery will only go down if alt is plugged in. Please look at my reply to Tech11 today and see if you can make any sense out of that. Thanks so much for your help.

[j cAT]

Originally Posted by vanharlin

You're correct. Pin D has full voltage but Pin L has none but Pin D has about .5 volts with battery ground cable disconnected. Could that just be backfeed? Being old school, I lean toward the alt also but why is the battery drain the same regardless if the alt is hooked up or not and at the same time, the battery will only go down if alt is plugged in. Please look at my reply to Tech11 today and see if you can make any sense out of that. Thanks so much for your help.

pin d is good you have 12volts engine/key off position. pin L has no volts on it so that would mean the alternator is not being turned on which is good this is from the PCM .

the drain then would be from the 12 volts that goes to the regulator which must be defective because it is drawing the current thru the alternator when the key is off.

you can check this by placing an ammeter between the connector pin D and the orange wire to see this current flow which is not supposed to occur with the key off.

auto zone here has a alternator tester . I would have it tested if this is possible in your area.

[stripe]

just a thought did you tighten the bolt too tight?

If you spin that main bolt to tight it will mess all.

Cheers
Stripe

[j cAT]

Originally Posted by vanharlin

I think I need to clarify that I have a 1.77 amp draw with or without the alt hooked up, however, the battery only goes down if the alt is hooked up. With alt unplugged the battery will maintain charge. Plulled all fuses in both upper and lower fuse blocks (underhood) today. Left I/P fuse (big 60 fuse)described in owners manual as left fuse (Battery) in upper block, dropped draw to 1.2 amps however killed everything in the car. RT I/P #3 fuse described as defogger & Audio system in lower block dropped draw to .57 amps. Its also a big 60 fuse. No other changes. Will leave the RT I/P #3 fuse out over night and see what happens. Thanks so much for your help. I,ll let you know the results.

the alternator disconnected you appear to have too much current drain. some vehicles draw about 200MA. that is .2 amp. your vehicle Is from what I have read is in the 30MA or .03 amp area. still if its below 200MA you should be OK.

now if you have the alternator NOT hooked up and you drawing 1.7AMPS that is a big load. I would guess this is a small light bulb. remove the small fuses after the vehicle has stopped running for a 30 min period. with the doors open the draw could be the security system , lock the vehicle and start the fuse pulling to see where this 1.7amp drain is from.

also you should start by removing the big red alternator wire and check for drain current. not just the small connector to alt.