Unknown battery drain

[04yuke]

I have an 04 Yukon that has developed an unknown battery drain. The battery checks out good. I've changed nothing. This mystery drain started 2 weeks ago. I had an fm transmitter with USB charge ports plugged into the aux power outlet. It's been there for months but thought that maybe it was the drain source and unplugged it. No help.
It's a gradual drain. Takes about a week to drain enough to need a jump.
This is a project vehicle and not my DD. Any suggestions for isolating the power leach would be appreciated. TIA

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[Doubeleive]

You will probably have to start pulling fuses to find it but some things that come to mind are the instrument cluster, interior lights, heater blower motor resistor, alternator resistor.

 

[UmmScott]

Like what double said...

Get a test light, disconnect the negative battery cable from the battery. Connect one end of test light to the negative battery cable and the other end to the battery.

If the light comes on then start pulling fuses till the light goes out. The fuse u pull that makes the light go out is the circuit thats giving u trouble.
Note: ECM/BCM circuits always have some draw.

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[04yuke]

Like what double said...

Get a test light, disconnect the negative battery cable from the battery. Connect one end of test light to the negative battery cable and the other end to the battery.

If the light comes on then start pulling fuses till the light goes out. The fuse u pull that makes the light go out is the circuit thats giving u trouble.
Note: ECM/BCM circuits always have some draw.

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I'll have to try the one-at-a-time plan I guess. I was a jeep guy prior to the Yukon. I'm still learning the quirks of the breed (like the blender door reprogramming). Just can't imagine what component decided to all of a sudden fail. Thanks guys.

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[UmmScott]

Again...doubeleive pretty much said this...just elaborating further.

You'd be suprised at how the blower circuits can trick you.
Listen carefully when the car is off in a quiet area.
A while back my mother had an 03 suburban that would drain the batt overnight. No lights left on, nothing obvious...
After carefully listening i found the front blower on the lowest speed when shut off. It would work on every speed normally when the car was on, but when u shut the car off it would sit there on low...barely able to hear or notice if ur not paying attention.
In this case, bad blower control module.

Dont forget the rear system as well! [emoji106][emoji106]

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[JonnyTahoe]

Again...doubeleive pretty much said this...just elaborating further.

You'd be suprised at how the blower circuits can trick you.
Listen carefully when the car is off in a quiet area.
A while back my mother had an 03 suburban that would drain the batt overnight. No lights left on, nothing obvious...
After carefully listening i found the front blower on the lowest speed when shut off. It would work on every speed normally when the car was on, but when u shut the car off it would sit there on low...barely able to hear or notice if ur not paying attention.
In this case, bad blower control module.

Dont forget the rear system as well! [emoji106][emoji106]

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[JonnyTahoe]

Again...doubeleive pretty much said this...just elaborating further.

You'd be suprised at how the blower circuits can trick you.
Listen carefully when the car is off in a quiet area.
A while back my mother had an 03 suburban that would drain the batt overnight. No lights left on, nothing obvious...
After carefully listening i found the front blower on the lowest speed when shut off. It would work on every speed normally when the car was on, but when u shut the car off it would sit there on low...barely able to hear or notice if ur not paying attention.
In this case, bad blower control module.

Dont forget the rear system as well! [emoji106][emoji106]

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My rear blower resistor did that on high last fall while I was just sitting in the truck with it completely off. Disconnected and removed it from the heater box Problem solved. My front heat works great and I could care less about rear A/C (no kids)

 

[04yuke]

Again...doubeleive pretty much said this...just elaborating further.

You'd be suprised at how the blower circuits can trick you.
Listen carefully when the car is off in a quiet area.
A while back my mother had an 03 suburban that would drain the batt overnight. No lights left on, nothing obvious...
After carefully listening i found the front blower on the lowest speed when shut off. It would work on every speed normally when the car was on, but when u shut the car off it would sit there on low...barely able to hear or notice if ur not paying attention.
In this case, bad blower control module.

Dont forget the rear system as well! [emoji106][emoji106]

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I've had the stereotypical blend door issues but I've not listened, or felt, for blower running (front or rear - thx johnnytahoe) with ignition off. I hear blend doors move from vacuum let-off in the WJ all the time, so, post ignition noises are not noticed. I'll be sure to check those out before the arduous fuse pull task. Thanks guys!!!

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[JonnyTahoe]

I was hearing clicking in the back of mine when I would turn the key on and when I would disengage the parking brake I had no clue what it was. Ended up being those rear Actuators (blend doors) disconnected them with positive results no more clicking.

 

[swathdiver]

I have an 04 Yukon that has developed an unknown battery drain. The battery checks out good. I've changed nothing. This mystery drain started 2 weeks ago. I had an fm transmitter with USB charge ports plugged into the aux power outlet. It's been there for months but thought that maybe it was the drain source and unplugged it. No help.
It's a gradual drain. Takes about a week to drain enough to need a jump.
This is a project vehicle and not my DD. Any suggestions for isolating the power leach would be appreciated. TIA

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Consider this: Truck sits for a few weeks and you drive it for an hour. Two weeks later you drive it for 30 minutes. Two weeks later you drive it for 2 hours. A week later you drive it for 30 minutes. What do you think the state of charge will be after all this time? I'll tell you what, it's going to be pretty low. Put a battery tender on it.

 

[04yuke]

Consider this: Truck sits for a few weeks and you drive it for an hour. Two weeks later you drive it for 30 minutes. Two weeks later you drive it for 2 hours. A week later you drive it for 30 minutes. What do you think the state of charge will be after all this time? I'll tell you what, it's going to be pretty low. Put a battery tender on it.

I just put a ctek tender on it. We'll see how it goes.

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[George B]

Consider this: Truck sits for a few weeks and you drive it for an hour. Two weeks later you drive it for 30 minutes. Two weeks later you drive it for 2 hours. A week later you drive it for 30 minutes. What do you think the state of charge will be after all this time? I'll tell you what, it's going to be pretty low. Put a battery tender on it.

This is true. I would use a tender to keep it up to *****. The short cycles are ******* the battery anyway.

 

[04yuke]

This is true. I would use a tender to keep it up to *****. The short cycles are ******* the battery anyway.

One went on it today!

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[OR VietVet]

When you do the test light test you can also do the alternator power up wire to see if the light dims considerably. Like has been said, there are draws, minimal, for "keep alive memory", like the clock at the dash and the mentioned modules. If you have an internal diode problem with the alternator that can drain a battery. Good luck.

 

[04yuke]

When you do the test light test you can also do the alternator power up wire to see if the light dims considerably. Like has been said, there are draws, minimal, for "keep alive memory", like the clock at the dash and the mentioned modules. If you have an internal diode problem with the alternator that can drain a battery. Good luck.

Good point. Thanks for the reminder.


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[04yuke]

Good point. Thanks for the reminder.


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If it was an alternator diode, would it still charge? Bc it does. Otherwise it's either death throws of the battery or a parasitic draw.

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[OR VietVet]

A diode is designed to allow current to flow one way. If it goes bad that means current flow is reversing thru it and that can drain a battery. It can still charge but eventually that will stop as well.

 

[Yukon_]

I have an 04 Yukon that has developed an unknown battery drain. The battery checks out good. I've changed nothing. This mystery drain started 2 weeks ago. I had an fm transmitter with USB charge ports plugged into the aux power outlet. It's been there for months but thought that maybe it was the drain source and unplugged it. No help.
It's a gradual drain. Takes about a week to drain enough to need a jump.
This is a project vehicle and not my DD. Any suggestions for isolating the power leach would be appreciated. TIA

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Have the Red & Black battery cables checked (even inside of the jacket) could be corroded. Would need to replace. A few years back my 07 Tahoe had this same issue, and after replacing the negative cable the issue was over.

 

[McIntosh777]

I have an 04 Yukon that has developed an unknown battery drain. The battery checks out good. I've changed nothing. This mystery drain started 2 weeks ago. I had an fm transmitter with USB charge ports plugged into the aux power outlet. It's been there for months but thought that maybe it was the drain source and unplugged it. No help.
It's a gradual drain. Takes about a week to drain enough to need a jump.
This is a project vehicle and not my DD. Any suggestions for isolating the power leach would be appreciated. TIA

Sent from my SM-G930V using Tapatalk

Im thinking one Bad Diode in Rectifier for the alternator can cause this.Its not a common problem but it does happen.

 

[OR VietVet]

Yea, lots of times the corrosion builds under the insulation and if bad enough you can see the swell of the insulation itself but sometimes not, but it is there. When you replace the cable you can cut open the insulation of the old cable and it will be loaded with white corrosion covering the wire. That creates a major source of resistance to electrical flow.