71' electrical question
Thread Starter
Instructor
Joined: Jun 2004
Posts: 211
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From: madison wi
71' electrical question
I own a 71' nom and put a brand new battery in it and it fires right up.
I'll go 3-7 days without starting it and it will need to be jump started.
What are some common causes and potential solutions to my issue?
appreciate any help on this,
thx,
Rick
I'll go 3-7 days without starting it and it will need to be jump started.
What are some common causes and potential solutions to my issue?
appreciate any help on this,
thx,
Rick
Instructor
Joined: May 2006
Posts: 223
Likes: 1
From: Kennesaw GA
Something is drawing current even while the key is off. Really the best way to check it is to disconnect the ground cable from the battery and put a test light in between the battery and the cable. If there is a current draw, the light will light up. Go through the fuse box and remove fuses until the light goes out, then you've found the circuit. Aftermarket devices such as alarms, stereos, and especially amps that aren't switched properly cause the most problem.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Originally Posted by GruntyPants
Something is drawing current even while the key is off. Really the best way to check it is to disconnect the ground cable from the battery and put a test light in between the battery and the cable. If there is a current draw, the light will light up. Go through the fuse box and remove fuses until the light goes out, then you've found the circuit. Aftermarket devices such as alarms, stereos, and especially amps that aren't switched properly cause the most problem.
Thats good advice, never heard of that!
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Well, that is one way to do it...and you will find A circuit that is drawing current. But, there may be more than one circuit drawing current. In order to find them all you need to pull every fuse in the fuse box...then use your test probe on each of the fuse terminals (you could also replace each fuse and remove it so you have just one fuse in at a time).
There's some excellent circuit diagrams in the Haynes Repair Manual which will also help you track down the problem.
If you have an ammeter you can get through this faster. For example the clock will draw around 50 to 100 milliamps so it will eventually drain a battery after a month or two of just sitting which is why most of us with working clocks have battery lockouts or just pull the battery terminals (ground first) until we need to go somewhere. In fact, if you have a daily driver there then your first stop is to the parts store for a battery terminal with a kill switch or battery lockout or battery disconnect or whatever they are calling them, so you can get around while you trouble shoot your problem.
Anyway...if you see something above 100 milliamps then that will be your main problem.
There's some excellent circuit diagrams in the Haynes Repair Manual which will also help you track down the problem.
If you have an ammeter you can get through this faster. For example the clock will draw around 50 to 100 milliamps so it will eventually drain a battery after a month or two of just sitting which is why most of us with working clocks have battery lockouts or just pull the battery terminals (ground first) until we need to go somewhere. In fact, if you have a daily driver there then your first stop is to the parts store for a battery terminal with a kill switch or battery lockout or battery disconnect or whatever they are calling them, so you can get around while you trouble shoot your problem.
Anyway...if you see something above 100 milliamps then that will be your main problem.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
I would use an ampmeter (multimeter in MA mode) connected between the battery and + cable as RR said. If you find more than about 100ma you have a problem. Places to check: Ctsy light timer died, AC fan running on low with key off, Underhood light staying on. The clock if it works, it only gets a pulse now and then. If it is none of these its time to start pulling fuses, do this with the meter connected and look for the drain to drop off.
