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#1 |
Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,336
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Dead Battery ?
Brand new battery. Went to start the 71 C/20 , nothing. checked to see if I left anything on, ignition switch off. Heater fan off, headlights off ? Battery has 1.9 volts....any ideas ?
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71 C-20 07 Magnum RT AWD |
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#2 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,396
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Re: Dead Battery ?
Start charging the battery. After a bit, see if the alternator is warm. That would mean that it has a shorted diode. I got two of them before I got a good one. If so, disconnect the battery from the system to finish charging it.
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#3 |
Registered User
Join Date: Jul 2018
Location: Catskill Mountains,NY
Posts: 8,477
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Re: Dead Battery ?
First off you need to charge the battery then see if there is a drain on it with a multimeter. Hook it up and see if there is a draw if so then start pulling fuses one at time while checking the meter . Helps if you run long leads so the meter is visable as you pull them
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Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary. |
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#4 |
Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,336
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Re: Dead Battery ?
Thanks fellas ! I worked on the horn button last weekend, wondering if it was possible that the relay stuck on ? I just returned from NAPA , they charged the battery for me. Will report back after I figure it out...Jack
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71 C-20 07 Magnum RT AWD |
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#5 |
Senior Member
![]() Join Date: Apr 2016
Location: Cypress, TX
Posts: 3,704
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Re: Dead Battery ?
Before you get too involved and a multimeter and all that jazz,... So you were working in the area of the horn button. If the horn relay were stuck on, that would sure drain your battery. The horn would be blaring, if you have a horn. Do you have a horn relay and no horn or disconnected horn?
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#6 |
Registered User
Join Date: Dec 2007
Location: Cottage Grove, MN
Posts: 57
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Re: Dead Battery ?
Had the same issue. Stuck horn relay.
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#7 |
Registered User
Join Date: Oct 2004
Location: saskatoon, planet earth
Posts: 690
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Re: Dead Battery ?
If your trouble started right after installing the new battery it's not impossible you bought a dud.
A few years ago I bought a brand new battery. I was constantly having to charge it. Checked a crap load of possible problems. I finally got pissed off and bought another battery. Never had an issue since. Truck sits 5 months outside in cold Canadian winters. In spring it fires right up.
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I got a bench seat baby, you don't have to sit over there. |
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#8 |
Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,336
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Re: Dead Battery ?
The battery was fine for weeks after I bought it. I got it recharged yesterday At Napa and reconnected it. Started right up. I would like to check for parasitic draw but unsure exactly how to do it. I have a dmm but was told I could ruin it if you don’t hook it up properly....thoughts ?
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71 C-20 07 Magnum RT AWD |
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#9 | |
Registered User
Join Date: Oct 2020
Location: Albuquerque, New Mexico
Posts: 474
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Re: Dead Battery ?
Quote:
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#10 |
Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,336
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Re: Dead Battery ?
Thanks I appreciate your help..Jack
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71 C-20 07 Magnum RT AWD |
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#11 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,630
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Re: Dead Battery ?
You don't even need a multimeter. A 12vdc test light can check for battery on the green wire that connects to the horn(s). If you see voltage there, the horn relay is stuck on.
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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#12 |
Registered User
Join Date: Apr 2010
Location: So Cal
Posts: 1,437
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Re: Dead Battery ?
>> I would like to check for parasitic draw but unsure exactly how to do it.<<
Connect the +(Plus) battery cable to the battery. Touching the -(Neg) battery cable to the battery should produce little to no spark. A very small spark from a radio memory connection (radio OFF) would be considered a small parasitic drain. the larger the spark, the larger the drain. Not very accurate, but incredibly reliable. That said, not all battery drains are constant. Some are intermittent and impossible to detect with a digital meter. Digital meters Sample, Display, Pause, Repeat. Digital meters tend to jump around and it isn't always easy to see if your connection is the problem or if the intermittent problem is part of the problem. A bad power antenna with a internal self resetting circuit breaker would drain a battery in four days, had me stumped. A Analog Ammeter connecting the battery cable to the battery is the best way to check for battery drain. After that antenna problem. i won't use anything else for a battery drain problem. Three digital meters could not show me what that 80 year old Instrument Panel Analog Meter could see.
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'67 GMC 2500, 292, 4spd, AC |
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#13 |
Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,336
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Re: Dead Battery ?
Thanks guys ! I determined it was the horn relay stuck. I didn’t have the green wire connected to the horn so no indication the horn push components where not in the right orientation. I do like the idea of using the amp gauge instead of the DMM, pretty cool idea...back to splitting firewood...thanks..
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