Parasitic Draw on Courtesy Lamp Circuit

[seanb98]

As the title states I am diagnosing a parasitic draw that kills the battery on a 1998 Suburban. Battery was replaced a few weeks ago thinking that was the issue since it was 5 years old which is the typical life expectancy of a battery anyway. However the new battery is getting drawn down after sitting for a few days.

Putting my meter inline I am getting a 0.18 amp drain, started pulling fuses until the drain went away and narrowed it down to the courtesy lamp circuit. Turned out all of the lights in the shop and don't see anything glowing anywhere around the vehicle.

So before I start working my way through the circuit with the power probe, is there any typical areas in the circuit to check out first? I don't have a wiring diagram, so I'm not exactly sure what all is fed by this particular fuse. Any suggestions?

Thanks

 

[RawbDidIt]

As the title states I am diagnosing a parasitic draw that kills the battery on a 1998 Suburban. Battery was replaced a few weeks ago thinking that was the issue since it was 5 years old which is the typical life expectancy of a battery anyway. However the new battery is getting drawn down after sitting for a few days.

Putting my meter inline I am getting a 0.18 amp drain, started pulling fuses until the drain went away and narrowed it down to the courtesy lamp circuit. Turned out all of the lights in the shop and don't see anything glowing anywhere around the vehicle.

So before I start working my way through the circuit with the power probe, is there any typical areas in the circuit to check out first? I don't have a wiring diagram, so I'm not exactly sure what all is fed by this particular fuse. Any suggestions?

Thanks

I think the ashtray light is on that circuit, as is the cargo light (not sure the cargo light applies on the burb), it might be on while it's closed.

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[seanb98]

I think the ashtray light is on that circuit, as is the cargo light (not sure the cargo light applies on the burb), it might be on while it's closed.

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Thanks, as mentioned I didn't see anything glowing from the interior when the shop lights were off, but I'll check the ash tray for sure. Another thing I was just thinking of checking was the lights on the vanity mirror.

 

[RawbDidIt]

Yeah, it's a pretty dim light to begin with, and I've heard a couple people say the switch can fail closed so it may not be bright enough to see without opening. Additionally, I think the shift position indicator is on the same circuit, may not have noticed it since it's normal for it to be on for a while with the keys of, and it doesn't "glow" the way you're looking for.

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[delta_p]

This happened to me once before and I traced it same way. I was working on the HVAC actuator and was in and out behind the glove box alot. The switch somehow broke or the box wasn't adjusted right (hard to remember now) and the glove box light stayed on. the light is so dim i never saw it until i went round unplugging bulbs after getting on the circuit by find which fuse.

You can get wiring in service manuals (any 96-99) should work here. https://www.gmt400.com/threads/88-95-service-manuals.43575/

 

[Jglew82]

I was gonna say, I had this same problem and it was my glove box light staying on. Finally found it when I pulled the bulb and the meter dropped back down.

 

[seanb98]

Hey folks, solved the issue this morning. Turned out to be the lights on the vanity mirror. The cover had broken and was no longer depressing the switch fully to turn it off. Disconnected the wire and the amp draw went away. Should be good to go now. Thanks for the suggestions!

 

[RawbDidIt]

Hey folks, solved the issue this morning. Turned out to be the lights on the vanity mirror. The cover had broken and was no longer depressing the switch fully to turn it off. Disconnected the wire and the amp draw went away. Should be good to go now. Thanks for the suggestions!

Thanks for sharing the fix, not enough people do that.

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