Author Topic: How to track down electrical draw?  (Read 3505 times)


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How to track down electrical draw?
« on: September 21, 2006, 01:22:08 AM »


My battery goes dead after 2-3 days of sitting.  The battery is new, alternator charges, and now I'm not sure how to start tracking down this thing?  I know it's probably simple, but is there some way to do it methodically and logically?



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Re: How to track down electrical draw?
« Reply #1 on: September 21, 2006, 02:59:52 AM »
You'll need an amp meter (mulit-meter), but it's fairly easy if it's one of the fused devices.

Turn the car off and remove the key. (Remember, there's a theft warning buzzer and it draws current!!) Now remove the Negative battery cable and place the multi-meter on the highest reading you can (usually 10 amps). Now hook one side of the amp meter (multi-meter) to the battery, and the other side to the unhooked negative battery cable. See what the reading is. If it's 0, then go to the next lowest setting on the meter. Continue until you get to the lowest setting on the meter OR you start getting readings. If you get a reading, you do indeed have a drain. Now remove one fust at a time from the fuse block until the meter goes to 0. What ever fues makes the meter go to 0, then this is the device(s) causing your problems. Now you have to find out what the problem is with that device.

If it's NONE of the fuses (you still get a reading with all the fuses removed), then you have a problem through the charging circuit or starting circuit. But let's see where this gets you first.

Remember, dome lights, trunk lights, underhood lights, etc... draw current so take that into consideration. Even clocks and radio memory circuits!!

Ed "Bert" Bertrand
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Re: How to track down electrical draw?
« Reply #2 on: September 22, 2006, 01:55:58 AM »
Also, previously discussed at the link below.  Recommended test procedure same as suggested above by Ed.

The final response from the originator of the thread explained what his problem was:

It appearse the issue was my "head space and timing: x-military guys will know what I mean.  Anyhow , I was cranking the ignition key too far back and taking the key out.  This, it seems, was keeping the generator light on (barely dim to see unless dark) and draining the battery after a day or so.

I found this by accident actually.

thanks for the help

« Last Edit: September 22, 2006, 02:03:06 AM by rich69rs »
Richard Thomas
1969 RS