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Discussion Starter #1
my wife got to spend several hours at her work parking lot last night due to our normally very reliable '98 e430 with 265k miles not starting. negative shout out to pennimen markit group inc. (doesn't even sound like a tow company - dispatched by 21st century insurance) for not showing up in the hour estimated, still not showing up 3 hours after the call, then still not showing up 20 minutes after the driver says "i'll be there in 5 minutes" & then shunting calls to voicemail... when i arrived, i found attempts to start led to a "click" from the engine compartment although the interior and headlights looked pretty bright. a few minutes on jumper cables with my trusty '83 accord was enough to get 'er started and then home.

once home (15-20 minute drive) i checked the battery and charging;
12.69 volts at rest door closed
14.30 volts while idling

when we awoke this morning;
10.64 volts
.68 amps draw with only that flashing red led in the radio knob, clock and whatever else these cars do with the doors closed and ignition off...

attached is a pic of my multi-meter as configured and attached between the negative post of the battery and the disconnected negative lead to be sure i'm measuring that draw correctly.

battery's a 6 year old interstate that says "6 year performance". it's out of the car and on the charger (oops, missed using my cheap code obd code reader before removal) and i plan to take it to my f.l.a.p.s. for load testing.

i see threads and youtube videos for diagnosing a parasitic draw. i've read the alternator (as far as i know, original to the car) can also be a source.

any tips or advice would be most appreciated. if any of our many helpful members (you know who you are!) ever come to san jose, i already feel like i owe a beer, dinner and more beer!

oh, the wife wasn't the least bit upset by all this. she kept apologizing to me... yup, she's a keeper!

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.68? That's a lot of draw. The normal draw should only be 0.030 - 0.050. You need to fully charge the battery and then do the draw test. You have to start pulling fuses and see which fuse drops the milli volts down.
 

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I would get the battery checked first. 0.68 amp is a big draw, but your battery must have run down so much that it has gone down to 10.64 Volts overnight. For 12 hours, you would drain 12 * 0.68 = 8 ampere-hours which is nothing for a healthy fully charged battery.

If possible, get the alternator checked as well. A proper test equipment should be able to detect and show diode opens and shorts within the alternator.

Also, make sure you measure the quiescent (dormant) current properly. After you take the key out, and all doors closed, give maybe 10 to 15 minutes for the modules to go to sleep with the meter connected to measure current. Make sure that no interior lights are left on.

Once you get the battery checked and fully charged, get the current draw reading as described above. Then you can start pulling fuses :). Note that most of the fuses do not carry power till the ignition is turned on (positions 1, 2). So there is no point in pulling them. Measure the voltage on the fuse. If it has voltage with the key in your pocket, then you can pull (circuit 30, or always on power).

Remember some circuits do not have fuses. Like the blower motor regulator. Sometimes it leaks current when the key is out, and causes some current drain.
 

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Discussion Starter #4
thanks for the input. since the battery was already at the store, i put the 17 year old interstate battery (our previous one) in after a charge and it got us started and back to oreilly where a nice young lady checked the alternator in the car with her device and said it was fine. the 6 year old battery was not (couldn't get details, somebody else tested that). her advice was to just replace the battery.

i'm a bit dubious but, we'll re-check for draw properly, after the car sits for at least 10-15 minutes.

new super start platinum was $194 with an $18 core (yikes!) and has a 3 year warranty. thought about shopping around (think that last interstate was $120-130) but, didn't want to be "that guy" who takes advantage of the service and then spends his dinero elsewhere...

should keep on this but, there's still tomorrow, the backup car and motorcycle are still good and the weather's beautiful out. i'm gonna hook the dogs up to the bicycle, pack a few cold beers and go ride in the park!
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Check to see if the blower fan are not continuously blowing with car off and key out. That is one source of parasitic power draw.
 

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Discussion Starter #6
started pulling fuses and find change when 4 & 7 are out. goes from about .78 to .24. what's strange to me is that the effect isn't immediate, takes 15-20 seconds. also, the motor's definitely not spinning.

as i recall, the resistor and fan were from an s class at pick-n-pull from a few years ago (the porcupine looking resistor and plastic fan housing). i'm inclined to replace the resistor and see if my current draw stays low. sounds like .24 is a normal level of draw with the key off.

thanks for the tips, i think this place has helped solve another!
 

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started pulling fuses and find change when 4 & 7 are out. goes from about .78 to .24. what's strange to me is that the effect isn't immediate, takes 15-20 seconds. also, the motor's definitely not spinning.

as i recall, the resistor and fan were from an s class at pick-n-pull from a few years ago (the porcupine looking resistor and plastic fan housing). i'm inclined to replace the resistor and see if my current draw stays low. sounds like .24 is a normal level of draw with the key off.

thanks for the tips, i think this place has helped solve another!
Normal current draw is 0.024A or less. Disconnect blower regulator. It runs unfused.
 

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Fuses 4 and 7 supply power several modules including the climate control, instrument cluster, etc...

Some modules are still alive or half awake, like the door control units, rooftop, EIS etc. They need to be able to process IR or radio signals, authenticate, and act upon the commands received. I prefer measuring current through the fuses (over the terminals on each fuse) which is much less intrusive.

The leakage from the blower regulator typically will not be enough to turn the blower fan.
 

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Discussion Starter #9
installed a new bosch german made resistor yesterday and i'm thinking "until we meet again and the case is solv-ed" (in my best inspector clouseau voice), unless witek_m thinks my current draw at fuse 4 below is too high?

after installation last night, battery voltage at the underhood terminals was 12.8. this morning it's 12.7.

i've measured amps passed between the terminals on the #4 fuse at .28 both last night and this morning, #7 at 0. mrboca, i had to pull the fuse. if i measured at the top of the installed fuse, should i still get the same reading? i was getting 0.

also learned how to use the climate control to check voltage (ignition switch position 2, hold "rest" button until left side of display shows "1", use "auto" button to scroll to "24". last night between 12.0 and 11.8, this morning 11.8.

last time my resistor failed, the fan stayed on after turning off the ignition.
 

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There is no point in measuring the current on fuse 7 as it is powered only if the key is in position 2.

Fuse 4 provides power to various modules (including the climate controller, instrument panel......) when the key is in your pocket.

The problem with measuring the current with the fuse replaced by a meter is that it is intrusive. When you remove the fuse and install the meter, you are basically waking up and resetting the electronics, and this takes power. So either you need to wait for some time till the things get settled and modules go into sleep state, or measure the current with no intrusion. The milli-voltmeter method measures the voltage on the installed fuse terminals which is the voltage drop on the fuse, as a milli-Ohm resistor. This method requires a highly sensitive meter, and knowledge of the resistance value of the fuse, and higher the current drain, more conclusive the results. A standard ATO 20-amp fuse has a col resistance of 3.4 mOhms, so if you read 3.4 mV, the current is 1 amp. For 0.3 amps, you would be reading about 1 mV.

What is important is the total battery drain, not just one fuse. I have a rear cam which is permanently drawing 0.68 amps. It does not bother me as it is a daily driver, and the battery gets topped up everyday by the alternator with 50+ mile commuting.
 

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Discussion Starter #11
ah, thanks for the clarification. i'll check again at the battery later.

if it's still close to the .24 amps i was seeing with the car at rest for 5-10 minutes and the blower module unplugged before the new resistor install, i'll consider "the case clos-ed"...
 

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Discussion Starter #12
well, back to square 1... at least this time, with a fresh battery, there are no more "honey, the car won't start" calls... she's been checking the voltage at the climate control (good girl!) and reports seeing 11.8 volts, usually before starting the car. i saw 13.5 with the car running.

measured current draw at the disconnected (for 10 minutes, doors closed - rear passenger window open to allow me to reach in) negative battery terminal; .9 amps! when i connect my meter, i can hear a slight "click" sound from near the central rear view mirror. not a mechanical click but, it sounds like it comes from a speaker. the unused car phone mike is up there.

started disconnecting things (still waiting 10 minutes before measuring);

the blower motor regulator - no change
fuse 4 - down to .55 amps
fuse 7 - no change

a few months ago, i replaced most of the interior lights with leds. is it possible one of these is drawing current?
 

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Does your car have tele-aid ? Telephone ?

I do not believe the interior LEDs will cause anything like that as they should not be powered with key out anyway.

Do you think you have a depleted battery because the reading on the climate controller is 11.8V ? Do not trust it. Use a proper voltmeter at the charge points.

Emergency call module is powered by Fuse 15 in the rear fuse panel. Check current on that fuse.
 

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Climate voltage read out is off by 0.6v, so 11.8 + 0.6 = 12.4v

It doesn't seem to be that bad.
 

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It depends when the the voltage measurement was done. If the battery was measured immediately after the charging, it will show higher. Also in my case the difference between the climate control, and the actual meter reading was as much as 1V when the engine was not running.
 

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Discussion Starter #16
not sure about tele-aid. car did have the phone handset in the center console with another unit in the dash. i've removed both.

battery at the charge points with a trusted meter after resting for an hour or two was 12.72.

here's a thought; am i waking modules by connecting my amp meter between the negative post and now disconnected cable? in other words, should i leave my amp meter connected with clips for 5-10 minutes and then measure?
 

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should i leave my amp meter connected with clips for 5-10 minutes and then measure?
Yes.
You are not waking them up though. You are powering them up. If you remove the fuse 4, you are removing power from all modules that fuse 4 powers (always on power). So when you connect the ammeter instead of the fuse, these modules get powered up, and it will take time for them to settle (sleep). The same goes for the ALL modules when you disconnect power from them and connect your meter in series. You should wait till the modules go to sleep to get quiescent current values. That is where a decent DC clamp-on meter is valuable as you take measurements without disconnecting anything.
 

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Discussion Starter #18
ah, thanks! ok, i have some clips i can use to clamp things together. i'll measure properly and report back...
 

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Also, before you measure the voltage on the charge terminals, put the low beams on for 30 seconds, and then measure after a minute. This will get rid off the surface charge. Some years ago, I removed the charging battery maintainer from the battery. The battery measured something like 12.8V. When I tried to start the car, it would not even click the starter relay. It was completely depleted.
 

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Discussion Starter #20
yay! after properly connecting my amp meter with clips and waiting 10 minutes so as not to power up any modules, i read .05 amps.

thanks all very much for all your patient help!
 
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