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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: slideways on September 29, 2025, 08:10:57 pm
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So i went on Amazon and bought a $12 USB outlet to swap into the ashtray. I verified i had 12v at the single wire and installed the outlet easy enough. Its a 2 pin with an inline fuse in the hot wire. I ran the ground over next to the parking brake to that 6 prong junction. It seems to work great. The only issue is i thought this was only hot with the key to IGN... turns out the little blue LED in the socket is on forever. Any ideas to fix this besides an obnoxious inline switch? I'm guessing it may take a week but that tiny blue LED will be dragging the battery down im sure. Or just find yet another one with no indicator LED?
Thanks
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As you discovered, the orange wire powering the cigar lighter is constant battery power (B+). Reconnect the USB power lead to accessory power so it is energized only when the ignition key is in the RUN and ACCESSORY positions. Depending on the year of your vehicle, run the power lead to an ACC cavity in the fuse box.
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While I agree with bd's assessment, how much voltage/current drain can you expect over how much time?
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Any ideas to fix this besides an obnoxious inline switch?
Would pulling the plug adapter from the socket be less obnoxious? I do that with my dash cam; when I'm parked in the garage, I don't need the dash cam on so I pull its adapter from the cigarette lighter socket just enough to disconnect it.
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How often do you drive the truck? Once every 2-3 months?
If yes, that tiny LED might drain a weak battery.
If not, forget about it and drive... ;)
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Every few weeks i try to get it out. I'm just wondering how quick it would drain it.
Zucchi there isnt anything to unplug on this one. Its not the adapter socket that goes into a typical cigarette outlet. Its an actual 3 slot usb socket itself with +/- on the backside which are tough to access. You have to remove the ashtray if you'd want to do that. I just unplugged the ground terminal by the park brake pedal for now.
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That blue LED draws only 20-30mA. That is less than half of what is considered acceptable parasitic draw, which is ~75mA. As long as nothing is plugged into the USB ports, it would take more than six months (arbitrarily) to impose any noticeable effect on a healthy battery's state of charge.