Very intermittent parasitic draw

[JohnMack]

Hello , I have a 2002 Buick LeSabre with 165k miles on it. I am experiencing a parasitic draw that pulls the battery down to a couple of volts over the course of approximately 10 hours. The issue is that it happens very infrequent , like once every 4 or 5 months. Every time it happens I try not to touch anything. I recharge the battery and do an amp draw test with an inline meter and everything is normal (after 25.minutes rest the draw is 18 millivolts). My battery is good and can't find anything obviously wrong.
Any thoughts on what I could do to try and narrow this problem down or things I could do to try and help me catch this acting up??
Thanks In advance for any help given.

 

[Rob_Roy]

It will be challenging to troubleshoot something that happens so infrequently. All I can offer is that I had something similar happen on a Lincoln one time and it turned out to be the radio.

 

[JavierH19]

once every 4-5 months? That's gonna be a tough one. Only way I could imagine is some kind of programmable low voltage alarm that triggers once it goes to 11v or less and to check it as it's happening with a voltmeter or maybe a thermal imaging camera to see what's getting warm. If this was my car I'd just keep a jump pack in the back. Maybe get one from harbor freight on sale next time.

 

[JohnMack]

It will be challenging to troubleshoot something that happens so infrequently. All I can offer is that I had something similar happen on a Lincoln one time and it turned out to be the radio.

Thanks for your reply. Ive been doing lots of digging on this and seems like others have had issues with radios too. It's something I check whenever this happens but have never seen it being stuck on but who knows.
Thank you, I'll continue to keep that in mind.

 

[JohnMack]

It will be challenging to troubleshoot something that happens so infrequently. All I can offer is that I had something similar happen on a Lincoln one time and it turned out to be the radio.

Thanks for your reply. Ive been doing lots of digging on this and seems like others have had issues with radios too. It's something I check whenever this happens but have never seen it being stuck on but who knows.
Thank you, I'll continue to keep that in mind

once every 4-5 months? That's gonna be a tough one. Only way I could imagine is some kind of programmable low voltage alarm that triggers once it goes to 11v or less and to check it as it's happening with a voltmeter or maybe a thermal imaging camera to see what's getting warm. If this was my car I'd just keep a jump pack in the back. Maybe get one from harbor freight on sale next time.

Thanks for your quick and detailed response. And I am going to take your advice and get a jump pack to keep in it for some piece of mind.

 

[Escape08]

Any aftermarket acc installs recently such as dashcams, alarm etc? And also may add, frequeny opening of doors makes the system wake up more often

 

[JohnMack]

Any aftermarket acc installs recently such as dashcams, alarm etc? And also may add, frequeny opening of doors makes the system wake up more often

Nope, nothing new added but thanks for the asking.

 

[supton]

I was thinking radio too. But it could be any light controlled by the body control module not being turned off properly. Intermittent problems are the worst. If it was more consistent, you could try to pull fuses and isolate it that way.

Jump pack is the way to go, short of disconnecting the battery.

 

[chemman]

Does your LeSabre have an OnStar module installed in it?

I do know that OnStar modules in some 2004 Chevrolet models have been known to be the source of intermittent parasitic drains. The solution has been to either pull the fuse for the OnStar module or to unplug it.

By the way, 2004 and prior years of OnStar are no longer supported, so the modules do nothing but potentially cause problems.

 

[50yr Street Mech]

On my 1989 Buick Regal Gran Sport, / 110k / had a parasitic draw that drove me nuts for 6 months. Checked everything. Even took it to an electrical shop for them to locate it. They could nit find it either,,,...Did some serious research in Haynes books...... In the end, it was the alternator of all things. Go figure that one.

 

[ka9mnx]

Just what I was going to mention, alternator. A leaky diode in the bridge rectifier could, intermittently, do that.

 

[JohnMack]

Does your LeSabre have an OnStar module installed in it?

I do know that OnStar modules in some 2004 Chevrolet models have been known to be the source of intermittent parasitic drains. The solution has been to either pull the fuse for the OnStar module or to unplug it.

By the way, 2004 and prior years of OnStar are no longer supported, so the modules do nothing but potentially cause problems.

Nope , no OnStar in this model but you are correct as I've seen posts about it causing battery drain issues.
Thanks for the reply.

 

[JohnMack]

On my 1989 Buick Regal Gran Sport, / 110k / had a parasitic draw that drove me nuts for 6 months. Checked everything. Even took it to an electrical shop for them to locate it. They could nit find it either,,,...Did some serious research in Haynes books...... In the end, it was the alternator of all things. Go figure that one.

Thats a good point , and one I really didn't consider. I kinda ruled it out as I was thinking that if something was shorted with the alternator it would always be shorted. I'll keep it in mind though if I can ever get the car to act up.

 

[JohnMack]

Just what I was going to mention, alternator. A leaky diode in the bridge rectifier could, intermittently, do that.

Yeah, I wasn't thinking alternator as it's so intermittent but if you think it's a possibility I'll focus on it if and when I get the car to act up.

 

[50yr Street Mech]

165k on an original GM alternator is just amazing by itself. Just take it out and have it tested at an auto electrical shop on the bench. Maybe the draw will come up on the test. Even if it's good, I'd be petrified to put it back in with those miles on it. I had an OE go on fire in a 1988 Chevy Celebrity with a V-6 in it. About 80k. Lost the whole car. POOF....GONE

 

[JohnMack]

@50yr Street Mech
Oh jeez, now you got me worried about that alternator, wondering if I should pull it out and have it rebuilt (we have a reputable shop in my town that still rebuilds starters and alternators).
I wouldn't worry an it too much but my kid is taking the car off to college 1500 miles away in fall.

 

[50yr Street Mech]

John, at the very least, have the alternator tested. 165k on a GM alternator should go in the Guiness Book of World Records. Do it for you're kid, for peace of mind. I sat on the guardrail and watched that Chevy Celebrity go up in flames. There was no stopping it. I saw smoke, pulled over, the alternator was on fire. The fire traveled down the harness like a fuse on a firecracker, right into the car. I moved away from the car and waited for the firetrucks, sitting on the guardrail. It was an 86'-87'-88' Celebrity. I forget. BUT..they do cause parasitic draws. I had a bunch of alt's do that to me already. Could be a warning sign for you. . That Buick pulls a lot of amps off that alt.. Lots of toys in it.

 

[JohnMack]

Alright , thank you for your input, after hearing your horror story you've convinced me to take it in.
I'm usually a run til fail type guy but also an extreme worrier so this will put my mind at ease.
Thank you...

 

[50yr Street Mech]

Glad to hear it. I have you're kid's best interest here. The rebuild will be cheap, and it may solve that intermittent draw problem too Good luck Make sure he/she gets a fairly fresh battery too before school starts. Even if it's a 2 year Walmart battery.

 

[JohnMack]

Thanks for your help with this.
Yes the rebuild is reasonable, Ive had this place do a similar GM alternator a couple of years ago and it was like $120.00ish.
As stated it's the original alternator and I my be wrong on this but I feel more confident on rebuilding it versus taking my chances of a "New" one from the chain store or online.