Battery drain - The 1947 - Present Chevrolet & GMC Truck Message Board Network

shooter · 05-19-2004, 11:26 PM

I have a 72 GMC Sierra Grande. Has new battery and Alt. Battery drains overnight. Any ideas?

walker · 05-19-2004, 11:29 PM

Look in the FAQ section I think there is a guide to finding a key off drain. Essentially you can connect an AMP meter on the battery cable and start pulling fuses till your amp meter reads zero.

shooter · 05-19-2004, 11:34 PM

Thanks Walker

da-burb · 05-19-2004, 11:40 PM

Does your horn work? The first place I look is the horn relay. If your horn works you get to look elsewhere.

I like to use a 12V test light to check for a draw. Same principle as the amp meter. Pull the fuse and put the ground to one side of the fuse block and the pointy part that you usually jab into your finger when testing a wire to the other. If there is something shorted in that circuit it will light up. That will at least narrow it down some.

Longhorn Man · 05-20-2004, 12:01 AM

I have to agree with da-burb on the horn...either that or a messed up alt. They can cause drain too.

Jeepster376 · 05-20-2004, 12:19 AM

Quote:

Originally Posted by da-burb

the pointy part that you usually jab into your finger

LOL

Ah yes that end.

shooter · 05-21-2004, 02:02 PM

I used a test light on each fuse separately. It lit up on all of them. The horn works. I removed the pos cable and the motor still runs. Any more ideas?

Longhorn Man · 05-21-2004, 02:08 PM

Check out THIS post, it'll give you a step by step procedure.
Sounds like you just probed the fuses...this means all your circuits are good.
By removing the battery cable with the engine running, you verified that the alt charges at 2 or so amps.

shooter · 05-21-2004, 09:37 PM

Longhorn Man,
Thats how I checked the circuits, from the post you left a link of. All circuits lit up test light.

CG · 05-21-2004, 09:43 PM

Quote:

Originally Posted by da-burb

Does your horn work? The first place I look is the horn relay. If your horn works you get to look elsewhere.

I like to use a 12V test light to check for a draw. Same principle as the amp meter. Pull the fuse and put the ground to one side of the fuse block and the pointy part that you usually jab into your finger when testing a wire to the other. If there is something shorted in that circuit it will light up. That will at least narrow it down some.

lol .... tossing da-burb a bandaid

sneakysnake · 05-21-2004, 10:30 PM

If you have checked each circuit?, With every thing turned off "unhook" the pos+ terminal from the battery and place a test light in series(one side to the battery and the other to the pos+ wire) the light should not light up if everything is ok. You may have diods in the alt. bleeding or like I had one time a under hood light on a pontiac that was staying on.
Just go though the wiring one by one un hooking components till the light goes out.

Longhorn Man · 05-21-2004, 11:25 PM

Hmm, try unplugging the ignition switch as you do the test.
I wonder if it is stuck in the ignition position or something.
You stated that the engine continues to run after disconnecting the battery, have you had problems with it not shutting off? Do the wipers work when the key is in the off position?

shooter · 05-22-2004, 11:55 AM

thanks I will try that

05-19-2004, 11:26 PM	#1
shooter Registered User Join Date: Aug 2001 Location: Atlanta(Cartersville)GA Posts: 194	Battery drain I have a 72 GMC Sierra Grande. Has new battery and Alt. Battery drains overnight. Any ideas? __________________ USMC SEMPER FI

05-19-2004, 11:29 PM	#2
walker Registered User Join Date: Jul 2003 Location: north of Phx AZ about 30 miles Posts: 698	Look in the FAQ section I think there is a guide to finding a key off drain. Essentially you can connect an AMP meter on the battery cable and start pulling fuses till your amp meter reads zero. __________________ Andy,Phx AZ '67 C-10 (Ahhh, done at last. Well there is that disk front end I want to put in and...) "23 C-Cab-sold '48 Ford 8N tractor(still working) '67 Scout(Now on the road) '70 MG B.-sold

05-19-2004, 11:34 PM	#3
shooter Registered User Join Date: Aug 2001 Location: Atlanta(Cartersville)GA Posts: 194	Thanks Walker __________________ USMC SEMPER FI

05-19-2004, 11:40 PM	#4
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	Does your horn work? The first place I look is the horn relay. If your horn works you get to look elsewhere. I like to use a 12V test light to check for a draw. Same principle as the amp meter. Pull the fuse and put the ground to one side of the fuse block and the pointy part that you usually jab into your finger when testing a wire to the other. If there is something shorted in that circuit it will light up. That will at least narrow it down some. __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

05-21-2004, 02:02 PM	#7
shooter Registered User Join Date: Aug 2001 Location: Atlanta(Cartersville)GA Posts: 194	I used a test light on each fuse separately. It lit up on all of them. The horn works. I removed the pos cable and the motor still runs. Any more ideas? __________________ USMC SEMPER FI

05-20-2004, 12:01 AM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I have to agree with da-burb on the horn...either that or a messed up alt. They can cause drain too.

05-21-2004, 02:08 PM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Check out THIS post, it'll give you a step by step procedure. Sounds like you just probed the fuses...this means all your circuits are good. By removing the battery cable with the engine running, you verified that the alt charges at 2 or so amps.

05-21-2004, 09:37 PM	#9
shooter Registered User Join Date: Aug 2001 Location: Atlanta(Cartersville)GA Posts: 194	Longhorn Man, Thats how I checked the circuits, from the post you left a link of. All circuits lit up test light. __________________ USMC SEMPER FI

05-21-2004, 10:30 PM	#11
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	If you have checked each circuit?, With every thing turned off "unhook" the pos+ terminal from the battery and place a test light in series(one side to the battery and the other to the pos+ wire) the light should not light up if everything is ok. You may have diods in the alt. bleeding or like I had one time a under hood light on a pontiac that was staying on. Just go though the wiring one by one un hooking components till the light goes out.

05-21-2004, 11:25 PM	#12
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Hmm, try unplugging the ignition switch as you do the test. I wonder if it is stuck in the ignition position or something. You stated that the engine continues to run after disconnecting the battery, have you had problems with it not shutting off? Do the wipers work when the key is in the off position?

05-22-2004, 11:55 AM	#13
shooter Registered User Join Date: Aug 2001 Location: Atlanta(Cartersville)GA Posts: 194	thanks I will try that __________________ USMC SEMPER FI



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