Need Battery Drain Experience '71 with A/C
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 19
Likes: 2
Need Parasitic Battery Drain Experience for '71 era Vette
I've read most of the posts dealing with battery drains but I just would like to know where people have found their drain on "71 era vettes with A/C. I've owned this '71 convertible for 42 years. It's completely stock, no aftermarket anything except the clock has been converted to quartz 6 years ago. It does not have electric windows. I measure .37 amp drain with two different multimeters and a test light lights when placed between the + terminal and + battery cable. Measures 2.3 amp drain when courtesy lights are on. I have: removed all fuses, disconnected antidieseling and blocking relay, disconnected alternator, TCS, A/C compressor, horn/buzzer relay, heater fan relay, and turned wiper override switch off and on, and no change in .37 amp drain. I'd just like to know where guys have found their battery drains before and maybe I can continue with those suggestions before I tear up the car anymore. Thanks so much for your help !!!!
Last edited by jacgillam; Nov 5, 2017 at 09:54 PM.
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 19
Likes: 2
"Hot" side from battery goes to 4 locations first
I've followed the electrical schematic and found that the "hot" side of the battery goes to 4 places first; The ammeter, the horn/door buzzer relay, the alternator, and the solenoid on the starter. So since I've disconnected the alternator and the horn relay already, the next step is to disconnect the solenoid and see if that eliminates the .37amp drain. I'll keep posting my results.
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 19
Likes: 2
Yea, I checked that first. Since I've had the car so long I usually know all of the little gremlins in the car that ruin crusin' plans like that glove box light so that's the first thing I went to. It's also on the same circuit as the courtesy lamps so when I removed the courtesy lamp fuse that should have stopped the drain but it didn't. Thanks for the feedback!!
Last edited by jacgillam; Nov 6, 2017 at 12:15 PM.
Burning Brakes
Joined: Dec 2005
Posts: 1,179
Likes: 100
From: cranford nj
What i did was get a test light, disconect the neg cable from the battery, with the doors closed touch the test light to the neg cable on one side and the neg posy on the battery with the other and start by pulling one fuse at a time, when the light goes out you found what circuit is causing the drain, now the fun begins to find out why
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Couple questions back to you. Does a '71 have a spare tire carrier lamp? Does it have the dome light delay timer when you close the doors? And does a '71 have the alarm button / hood switch located on passenger side by the firewall?
Last edited by HeadsU.P.; Nov 6, 2017 at 12:59 PM.
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 19
Likes: 2
No, it doesn't have any of that, no courtesy lamp delay, no alarm system and no spare tire lamp under the car. And like I said, I've removed ALL of the fuses and the drain doesn't change. Thanks for the response and trying to help though.
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 19
Likes: 2
What i did was get a test light, disconect the neg cable from the battery, with the doors closed touch the test light to the neg cable on one side and the neg posy on the battery with the other and start by pulling one fuse at a time, when the light goes out you found what circuit is causing the drain, now the fun begins to find out why
of the fuses and replace them one at a time to find which circuit had the drain but when I removed all of the fuses, the drain didn't change So the drain is not in a fused circuit that is fused under the dash. Thanks for trying to help though.
I'm going to get under my car and disconnect the starter solenoid wires next.
Last edited by jacgillam; Nov 6, 2017 at 04:06 PM.
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Race Director
Joined: May 2006
Posts: 18,742
Likes: 2,583
the .37 number is definitely amps not milliamp?
when you pulled all the fuses, you looked at the clock and it was no longer moving?
I know you say everything is stock, just to clarify, you have the stock radio?
no aftermarket alarm system?
when you pulled all the fuses, you looked at the clock and it was no longer moving?
I know you say everything is stock, just to clarify, you have the stock radio?
no aftermarket alarm system?
Race Director
Joined: May 2006
Posts: 18,742
Likes: 2,583
this chart shows milliamp draw on modern cars that will kill batteries over a month or more so 370 is a pretty big draw and might kill a battery in a week or so
http://www.flashoffroad.com/electric...rrentdrain.pdf
http://www.flashoffroad.com/electric...rrentdrain.pdf
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 19
Likes: 2
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 19
Likes: 2
this chart shows milliamp draw on modern cars that will kill batteries over a month or more so 370 is a pretty big draw and might kill a battery in a week or so
http://www.flashoffroad.com/electric...rrentdrain.pdf
http://www.flashoffroad.com/electric...rrentdrain.pdf
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 19
Likes: 2
this chart shows milliamp draw on modern cars that will kill batteries over a month or more so 370 is a pretty big draw and might kill a battery in a week or so
http://www.flashoffroad.com/electric...rrentdrain.pdf
http://www.flashoffroad.com/electric...rrentdrain.pdf
Last edited by jacgillam; Nov 6, 2017 at 07:34 PM.