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

Martin64 · 12-27-2003, 08:32 PM

I have a small power drain in my '70 that I'm trying to narrow down. It drains the battery in about 36 hours. What are all the items that have direct power besides the light switch and starter? I'm thinking my ignition switch may be the problem but I haven't had a chance to test it yet. When I dosconnect the battery I can hear something "click".... open relay? What relays stay hot (direct powered) on the firewall?

There is no stereo or amp or anything like that installed so that's not a problem.

**old Rusty C10** · 12-27-2003, 08:41 PM

other than ignition switch and headlights is the cigarette lighter brake lights and maybe the horn im betting its in the ignition tho

cdowns · 12-27-2003, 08:43 PM

the horn relay is hot all the time
best thing to do is remove 1fuse at a time using a test light to see where the drain is

da-burb · 12-27-2003, 09:17 PM

does your horn work? It is the first place I go when I have a battery drain. It has been the problem more times that it hasn't.

Martin64 · 12-27-2003, 09:18 PM

No cigarette lighter and the horn is disconneted (because it stuck on me once.....that was funny/embarrassing). The brake light does stay on sometimes but I'm now in the habit of checking it when I get out of the truck...... thanks again gents for the help!

Martin64 · 12-27-2003, 09:31 PM

What does the "Transmission Spark Control" relay do and is it a direct wire?

**john** · 12-27-2003, 09:53 PM

Did you just unhook the horn wire or unhook the power to the relay? The relay can still drain power if it is the prob. The TSC relay could be another source. If it is not working I would just unhook it. good luck The TSC allows vacuum advance only in high gear. John

Martin64 · 12-27-2003, 10:00 PM

Good point about the horn, I hadn't thought about that..... when it stuck on me I just figured it was stuck at the horn button on the steering wheel and when I couldn't get it off quick enough I just pulled over and unhooked it from the horn. So since it's still "hot" and grounds through the bracket that still completes a circuit.

12-27-2003, 08:32 PM	#1
Martin64 Registered User Join Date: Oct 2003 Location: Yuma, Az Posts: 477	Battery Drain Problem I have a small power drain in my '70 that I'm trying to narrow down. It drains the battery in about 36 hours. What are all the items that have direct power besides the light switch and starter? I'm thinking my ignition switch may be the problem but I haven't had a chance to test it yet. When I dosconnect the battery I can hear something "click".... open relay? What relays stay hot (direct powered) on the firewall? There is no stereo or amp or anything like that installed so that's not a problem. __________________ Martin Gibson USAF Retired 1964(-ish) C10

12-27-2003, 08:41 PM	#2
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,316	other than ignition switch and headlights is the cigarette lighter brake lights and maybe the horn im betting its in the ignition tho __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

12-27-2003, 08:43 PM	#3
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	the horn relay is hot all the time best thing to do is remove 1fuse at a time using a test light to see where the drain is __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

12-27-2003, 09:17 PM	#4
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	does your horn work? It is the first place I go when I have a battery drain. It has been the problem more times that it hasn't. __________________ 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

12-27-2003, 09:18 PM	#5
Martin64 Registered User Join Date: Oct 2003 Location: Yuma, Az Posts: 477	No cigarette lighter and the horn is disconneted (because it stuck on me once.....that was funny/embarrassing). The brake light does stay on sometimes but I'm now in the habit of checking it when I get out of the truck...... thanks again gents for the help! __________________ Martin Gibson USAF Retired 1964(-ish) C10

12-27-2003, 09:31 PM	#6
Martin64 Registered User Join Date: Oct 2003 Location: Yuma, Az Posts: 477	What does the "Transmission Spark Control" relay do and is it a direct wire? __________________ Martin Gibson USAF Retired 1964(-ish) C10

12-27-2003, 09:53 PM	#7
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Did you just unhook the horn wire or unhook the power to the relay? The relay can still drain power if it is the prob. The TSC relay could be another source. If it is not working I would just unhook it. good luck The TSC allows vacuum advance only in high gear. John __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/ Last edited by john; 12-27-2003 at 10:00 PM.

12-27-2003, 10:00 PM	#8
Martin64 Registered User Join Date: Oct 2003 Location: Yuma, Az Posts: 477	Good point about the horn, I hadn't thought about that..... when it stuck on me I just figured it was stuck at the horn button on the steering wheel and when I couldn't get it off quick enough I just pulled over and unhooked it from the horn. So since it's still "hot" and grounds through the bracket that still completes a circuit. __________________ Martin Gibson USAF Retired 1964(-ish) C10 Last edited by Martin64; 12-27-2003 at 10:03 PM.

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