1994 Honda Civic How to check for small electrical flow

AMHOZAA

MEMBER
1994 HONDA CIVIC
4 CYL
FWD
MANUAL
185,000 MILES

Hi, we have a 1994 Honda Civic w/ a very slow battery drain. At around the 5-6 hr mark, the battery is completely dead. We have checked all the fuses and have determined that the 20A Wiper Washer fuse still outputs 36 mA when we take out the fuse and test w/ a multimeter, and the 7.5A starter signal fuse puts out 1.1 mA. All the rest of the fuses test OK. How do we go about finding out why these fuses are still outputting electric flow while the car is turned off?

7 Replies

WRENCHTECH

MECHANIC
20,761 POSTS

Are you sure about those numbers because they are not excessive enough to drain a good battery. Most cars have an acceptable parasitic draw limit of about 50ma.

To kill a good battery in 5 hours would take about 10,000ma which is 10 amps

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Friday, August 27th, 2010 AT 1:14 PM

KHLOW2008

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Hi AmHozaa,

Thank you for the donation.

The wiper fuse is shared by Moon Roof relays, Windshield Washer Motor, Rear Window washer Motor, Integrated Control Unit, Windshield Wiper Motor, Rear Wiper Motor, Power Window relay.

Both fuses should be hot only when ignition switch is turned on therefore there is no reason for them to be the cause. It could be a reverse flow of currect from another source.

At miliamp rates, it should not be a problem.

There are many instances of sticking relays causing parasitic drains as the relay is constantly supplying battery voltage. When the battery terminals are disconnected, the relay opens and problem stops. Under such circumstances, the test would be non conclusive.

Check if the radiator fan or any other components are working when engine is turned off.

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Friday, August 27th, 2010 AT 1:22 PM

AMHOZAA

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Ah, thx for the 'acceptable parasitic draw' info. Couldn't find that. Also, for how much it would take to drain the battery in roughly 5-6 hrs.

So, yep, that's what the fuses measured. What's next to check? Battery is new and tests fine at 2 different local auto supply stores; alternator is 2 yrs 4 mos old. Problem started around April this yr (alternator and battery replaced April '08; battery again replaced this April.) Our temp fix is to disconnect the neg terminal on the battery every time we drive. Some long dist; most short (less than 1/2 hr drive) each time we drive. I've read that longer trips are needed to fully charge the alternator; tho that doesn't seem to affect the drain time. Still drains even after a longer trip.

Again, what's next to test? (Also, check engine light is on, but that is NEW - only in the last 2 weeks; have not yet taken it in to get code.)

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Friday, August 27th, 2010 AT 1:39 PM

WRENCHTECH

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300 to 400 would kill it over a couple days.

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Friday, August 27th, 2010 AT 2:00 PM

AMHOZAA

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As far as we've checked, the radiator fan nor anything else is on or still working when the engine is off. This is a very basic model - no power window, nor power doors, no sunroof, etc. Not even a light in the trunk NOR the glove box!

Is there any way to check if those components ARE on? We HAVE checked to see if the alternator is warm to touch after sitting off for several hours; it's not. However, that's a subjective thing. Something I might (or my husband might) consider not warm, another might.

Any more clues?

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Friday, August 27th, 2010 AT 9:32 PM

SEATAZZZ

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I would suspect the alternator. If you have a voltmeter, check the alternator output while engine is running with no load. Normal output is supposed to be between 13-15. If less than 12v, then alternator is not charging enough. This is enough to drain the battery over normal driving conditions (had the same thing happen in my Honda/Isuzu Passport). Connection could be loose, or it's just a bad alternator. Also check the alternator belt--a loose or slipping belt can also affect the alternator output/battery use. I'm not a tech, just a home mechanic. Les Schwab will also test the alternator, probably for free.

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Friday, August 27th, 2010 AT 10:18 PM

WRENCHTECH

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I think the first thing you need to do is get a good reading on what the draw actually is. You have to first get an accurate measurement on what the draw really is before you can determine what the draw is or if you even have a problem. So far your numbers don't indicate a draw.
Here is the proper procedure.

You will need a digital ammeter and a jumper wire with clips on the ends to do this.
First rig any door switches so you can have a door open without triggering the interior lights and unplug the hood light. Remove one battery cable and attach the meter in series between the battery cable and battery post. Take the jumper wire and also attach it the same way. Leave the jumper wire on for at least 10 minutes to expire all the automatic timers. Now remove the jumper wire and read the meter. Anything over 50ma is too much draw. The way you locate this is to start removing fuses one at a time until the meter drops to normal level. This will be the circuit with something staying on. Determine what components are part of that circuit and check them individually until the problem is isolated.

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Saturday, August 28th, 2010 AT 6:52 AM