weird parasitic draw on battery EDIT SOLVED

[brian barton]

as it says i have a weird parasitic draw on a 2000 chevy silverado 1500 with 5.3L  battery when shut off.   i have done the parasitic draw tests 3 times now. twice with a multi-meter and once with a test light.  it shows a draw of 11.5-12a while shut off key removed doors closed no lights or accessories running.
removed ground wires *(2 heavy gauge ground wires) and tested with multi-meter. while watching the meter every single fuse was pulled and reinserted with no difference in draw. all relays were also removed and reinserted also with no difference in draw load.
my brother and i are both industrial electricians but DC is wildly different than AC.
the 130A alternator was put new today long with a new battery.

the only thing i can think of at this point is possibly a faulty ignition switch that is passing current to something... but once again i've checked all fuses and relays and nothing changes anything..

any ideas would be appreciated.

Edited November 16, 2020 by brian barton

[Charles_Colfax]

Following.
I'm chasing one on mine too.
Have mine narrowed down to something in the radio wiring.
These trucks are brutal with electrical gremlins.
I've had bizarre ground issues... That's what I've ended up finding a couple times.

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[riverbanks]

Sometimes you have to disconnect every module,one by one,there are a lot of them,radio,yup,it helps to check codes "u"codes,might narrow it down faster

[kickass audio]

is your radio aftermarket or factory? I know some aftermarket units that have GM chime adapters or steering wheel controls have problems where they draw a ton of power when they go bad. If you have an aftermarket radio look for a tiny black box usually buried in the dash or behind the radio, if you have it, disconnect it and check your draw level.

 

Do you also have any huge corrosion on the trailer connector at the rear that may be causing a short?

[brian barton]

1 hour ago, kickass audio said:

is your radio aftermarket or factory? I know some aftermarket units that have GM chime adapters or steering wheel controls have problems where they draw a ton of power when they go bad. If you have an aftermarket radio look for a tiny black box usually buried in the dash or behind the radio, if you have it, disconnect it and check your draw level.

 

Do you also have any huge corrosion on the trailer connector at the rear that may be causing a short?

aftermarket radio but no steering wheel controls are anything of the sort...  even went as far as unplugging the entire fuse box in the dash... still nothing stopped the draw...

[Charles_Colfax]

Sometimes you have to disconnect every module,one by one,there are a lot of them,radio,yup,it helps to check codes "u"codes,might narrow it down faster

What are "u" codes?

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[Charles_Colfax]

is your radio aftermarket or factory? I know some aftermarket units that have GM chime adapters or steering wheel controls have problems where they draw a ton of power when they go bad. If you have an aftermarket radio look for a tiny black box usually buried in the dash or behind the radio, if you have it, disconnect it and check your draw level.
 
Do you also have any huge corrosion on the trailer connector at the rear that may be causing a short?

Aftermarket here too.
I've got all the adapters for steering wheel controls, factory Bose amp, and integrated satellite radio.

I've got to make some time to pull the dash apart and go thru everything

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[brian barton]

SOLVED.... the issue was the alternator... the rectifier was faulty and allowing backflow...  *(yayy advance auto budget alternator)

also added 2nd ground cable for good measure... 

[kickass audio]

4 hours ago, brian barton said:

SOLVED.... the issue was the alternator... the rectifier was faulty and allowing backflow...  *(yayy advance auto budget alternator)

also added 2nd ground cable for good measure... 

Glad you figured it out! Did you run a diode test on the alternator to find that out? I never even considered a possible draw issue on the alt when it's shut down.

[brian barton]

42 minutes ago, kickass audio said:

Glad you figured it out! Did you run a diode test on the alternator to find that out? I never even considered a possible draw issue on the alt when it's shut down.

yes...after removal tested it on the countertop tester... it tested bad... installed new one... charged battery completely... checked with amp meter a big fat 0 draw with everything turned off...

i am happy... cause it was scaring me that i'd have to spend more money than the truck is worth...  

[Charles_Colfax]

SOLVED.... the issue was the alternator... the rectifier was faulty and allowing backflow...  *(yayy advance auto budget alternator)

also added 2nd ground cable for good measure... 

Dang. I haven't touched my truck in weeks.
But now may have to look in to this.
It's the original alternator... From 2006, 14 years and 105,000 miles.
Like you, I'll start with pulling the radio fuses first.
I'll pull the battery and fully charge it overnight too.

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