johnlvs2run

I got a 99 honda civic ex in march, and the battery drains overnight.
The first battery was fine for a few months, then went dead, which happened soon after disconnecting fuse #23 to the srs air bags. Now the red srs light stays on all the time when I'm driving. The new battery keeps draining fast the same way that the old one started doing. I'm not driving the car, because of the drain. I leave it in the garage with the cables disconnected, and give it a good charge once a week.

The multimeter volts test 13.14 terminal to terminal, 13.14 clamp to clamp, and 13.14 from the positive clamp (or terminal) to the negative bolt on the frame of the car. The cables don't tighten very well (I can pull them off) but appear to not be losing any drain. I'm planning to get new cables.

Here are the results of checking the under hood fuse box next to the battery.
.62 amps - total drain before pulling any fuses
.10 amps - fuse #10/43 - 7.5A - interior light <--- individual fuse
.40 amps - fuse #12/47 - 7.5A - back up & radio <--- individual fuse
.12 amps - fuse #13/51 - 20A - door lock, roof <--- individual fuse

This adds up to the .62 amps.
I'm thinking to test the SRS airbag system and capacitor first, as the drain is most likely coming from there. My idea is to remove the battery clamps, touch the cables together to make sure the SRS capacitor is drained, disconnect all of the yellow SRS connectors (will need to determine how many there are), and then retest the battery drain.

Any helpful ideas of how to do this and if I'm on the right track are much appreciated.
I have removed the front of the previous owner's fancy radio, which could be a possiblity too. There is no interior light saying on, except the SRS light, and everything else seems to be functioning well.

Former User

Explain how did you do these^ tests. What is the meaning of #10, 12, and 13?

I don't understand why you think the SRS system is the source of a drain. Does the SRS light stay on with the key off?

johnlvs2run

Those are the under hood fuse #s from the 1999 honda civic owner's manual. I disconnected the negative battery cable, set the multimeter black on com, red on amps, dial on 20, connected one wire to the negative cable, the other to the negative terminal; then removed the fuses one at a time, tested again, and replaced them. The 3 drains showed up in the first 5 fuses tested.

I feel the SRS is the source of the drain because the original battery was fine and charged well before the light began staying on. The light does not stay on with the key off, but my understanding (thanks to lazlong) is that the SRS airbag capacitor keeps charging when any SRS disconnection has been detected (such as #23 fuse removed), or when the SRS light stays on, and drains the battery.

Former User

Here's a diagram of the hood fuse box. Which fuses numbers correspond to your #10, 12, and 13 fuses?



20 Amp scale? Is there a lower amp scale to choose on your meter?

Are you reporting the calculated amp drain from each fuse or the amp reading from the multimeter. Please clarify how you came up with the amp drain figures you posted. The proper way is to calculate the difference between amp drain before and after fuse is pulled.

You would need to calculate amp drain before and after removal of fuse 23 to know whether the SRS system contributes to the drain.

johnlvs2run

That's cool. I wondered why they duplicated the same #s as under the dash, but with different functions.
10 = 43
12 = 47
13 = 51

This is my multimeter (shown here). With the black wire in com and the red wire in 20A, nothing showed in any of the 20/200m/20m/2m settings. I moved the red wire to mA, the wheel to 20, and got the .62 amp reading.

The .62 amp reading is the total shown on the multimeter before pulling any fuses.
The individual drains are as shown for each fuse, as shown in post #1, with more detail added for clarification.

I'm not interested in fuse #23, and have no plans to put it back in. There was probably much less drain with it in, since the SRS capacitor would not keep draining the battery if no disconnect was detected. Likewise, the battery was fine and did not drain prior to the SRS fuse #23 being pulled. This is why the SRS airbag system is the likely cause of the battery drains.

Former User

If you dial the wheel to the more appropriate 200m range and leave the leads where they are, do you obtain the same readings?

To pinpoint the source of the drain, unplug the radio,clock, and ECU (fuse 47 drain) and power locks and moonroof (fuse 51 drain). Most of the drain comes from fuse 45, which as you can see is an empty slot. A previous owner probably tapped into this slot to get power for an accessory. Trace the wire coming from this fuse slot. Alternatively, the drain is coming from a bad hood fuse box.

This idea makes no sense as fuse 23 only draws current when the key is in ON(II), typically when the engine is running. If there is excessive drain from fuse 23, the drain would be compensated by current produced by the alternator. Have you tested the alternator?

johnlvs2run

I don't recall, but will check that in the morning.

Is your chart from a 2000 honda? Mine is a 1999, and my results above are posted from the chart in the 1999 honda civic owner's manual. Apparently the 2000 fuse positions and functions are different, especially as the numbers are different. I think we should stick with the 99 chart, names and functions.

Why do you feel there's a drain from slot #45 (5) in my car? How would I test to see if the fuse box is bad, and why do you feel that might be an issue?

My understanding is that the SRS system keeps it's own power charge in an SRS capacitor, regardless of the key being on or off, as long as the battery is connected. Therefore it doesn't matter if the key is on or not. I have not tested the alternator or the starter.

Former User

With only a few minor differences, the fuse box diagrams for 96-00 Civics are the same. For the four fuses that concern you (23 , 43, 47, 51), 96-00 Civics are identical. My information is taken from the 96-00 Civic service manual, which provides MUCH more detailed information than your owner's manual.

I referred to fuse 45 based on your (incorrect) conversion of owners manual fuse 10 to service manual fuse 45. You actually should have typed fuse 43. In this case, check the dome light, trunk light, and DLC connector for the source of the fuse 43 drain.



First unplug components protected by each of the three hood fuses to see whether the abnormal drain is eliminated.

Not sure where you got your information, but it is incorrect. The SRS system draws ALL of its power through dash fuses 13, 23, and 25 via the ignition switch and hood fuse 42.

dewey_civic

iTrader: (1)

Did your alternator heat up at all? I think I am having the same issue. I noticed my alternator was warm with out the car being on. The next day the battery was did.

johnlvs2run

I'm not sure what a DLC connector is, or how to find shorts in that or the lights.

Unplug them from the fuse box? Do I remove the fuse box, then unplug them? Then how would I test them after that?

Are you saying the SRS system is not causing any drain?
Am I safe from the airbags going off with #23 fuse pulled, or is it possible they could still go off any time?

johnlvs2run

That I don't know. I've been leaving the cables unconnected.

Former User

Yes

Yes

DLC = data link connector where you would plug in a code reader. It's under the dash near the hood release lever.

Start simple. Check the DLC connector for bent terminals and remove the dome and trunk light bulbs. The trunk light is a very common source of parasitic drain.

Also unplug the radio, clock, ECU, power lock control unit, and the moon roof open relay.



Yes, that is what I am saying.

Are you concerned about an airbag malfunction or do you have an air bag phobia? If the latter is true, you should have a professional remove the airbags from your car.

johnlvs2run

RonJ@HT, you are awesome.
Thank you for taking the time to answer my questions in detail.

This helps a lot.

Yes I am very concerned about an airbag malfunction, and would love to remove them myself.
Does having a phobia qualify a professional to remove them for me? If so, it would probably be expensive.

I'll try the trunk light first. Thank you very much!

Former User

Hey, no problem.

I mentioned a professional because if done improperly, you could accidentally deploy an airbag during removal. In addition, after removal, the airbags must be purposely deployed prior to discarding them to prevent others from being injured.

apexi_rsx

id also check to see if your brake lights are staying on as well. if that plastic stopper falls out or breaks it will cause the lights to stay on and drain the battery.

johnlvs2run

Previously, I got the following results with my dt9205a multimeter (shown here).
red wire in 20A -- nothing showed in any of the 20/200m/20m/2m settings
red wire in mA -- wheel on 20 -- result = .62
I thought that was amps, as there was no other result.
Thanks to RonJ's helpfulness, that was not really an amp result, and perhaps were milliamps.

The result this morning was unexpected (based on what I thought were the amps).
The first thing that I did this morning was to open the trunk, and check the drain at the battery, as follows.
red wire in 20A -- wheel on 20 -- result = .19 amps (190 mA)
Therefore, there appears to be no significant drain from the battery, or the SRS system.
Correction: .19 amps = 190 mA = drain way too high when trunk open

What can I do to find what is causing the drain on the battery?
Also, where can I find a detailed 96-00 Civic service manual? Thanks very much.

Former User

0.19 A (190 mA) is still an abnormally high drain.

But I still don't think you have your multimeter configured correctly to make accurate measurements in the desired mA range.

If you move the red wire to mA and turn the wheel to 200 mA, what mA drain do you now measure?

johnlvs2run

Trunk closed
red wire mA -- wheel 200 mA -- result = 6.2

Trunk open (light on)
red wire mA -- wheel 200 mA -- result = off the chart, a big 1 to the left side of the screen.
red wire mA -- wheel 20 -- result = off the chart, a big 1 to the left side of the screen.
red wire 20A -- wheel 20 -- result = .19
red wire 20A -- wheel 200 mA -- result = 1.9

johnlvs2run

If my understanding is correct, the measured drain is 6.2 mA, which is very small and is not enough to drain the battery overnight.

The trunk light has a high drain when the trunk is open, but not when the trunk is closed.
Therefore something is draining the battery that is not showing up as a drain.

This brings me back to suspecting the SRS system, though the drain could still be from other things too.

Suggestions & ideas are much appreciated.

Former User

Right -- 25-50 mA of drain is normal.

Your parasitic drain tests take the parasitic drain idea completely out of the picture. Period.

Test your battery and alternator. For example, what voltage do you measure across the battery posts with:

1) The engine off.
2) The warm engine idling with all electrical accessories off.
3) The warm engine idling with many electrical accessories on (high beams, rear window defogger, A/C MAX).

johnlvs2run

Wonderful! Thank you.

engine off
13.41 - right after charging
13.14 - a couple minutes after charging (usually goes down to 12.89)

engine on
14.40 - no accessories
14.31 - lights
14.29 - high beams
14.21 - blower fan on high
14.12 - a/c on high (plus everything else)

engine on (reversing the sequence)
14.23 - high beams (a/c & blower off)
14.23 - regular lights
14.29 - no accessories

engine off
13.41 - right after turning off
13.25 - a minute after turning off (usually goes to 12.89)

Former User

Your alternator and battery appear to be fine, though your battery voltage with engine off seems to be about 0.5V high.

Read the manual for your multimeter to verify that you are really only reading 6.2 mA of drain. Just wondering whether the reading must be corrected for the mA scale used. If you have a link to an electronic version of the manual for your multimeter, post it. Also post a picture of your meter reading the mA drain.

johnlvs2run

That is good. Thank you. What should be the highest V that I charge the battery?

The manual was only a little piece of paper, mostly in chinese.
People have posted that the multimeter functions the same as other multimeters.

What can I do to reduce the trunk light drain when it's on? Use a lower wattage light?

apexi_rsx

if its an interior trunk light i would just take it out or use a led light which uses the least energy. or maybe you should integrate a kill switch to kill all electronics in the car when switched off.

johnlvs2run

Thanks. I will take it out in the meantime.