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Discussion Starter · #1 ·
IMO, when the vehicle is turned off, there should be zero voltage being used.

Take the ground lead off of the battery. With the vehicle turned off, test between the ground lead, and the gound post on the battery. If you get any voltage, then that voltage is draining the battery while the vehicle is turned off.

Howsomever....

If you have things like a radio that has station presets, etc... Then that would be a low, very slow drainage, but it WOULD show some sort of voltage in the above test.

I do have a radio that has the presets. But I think that is all that I have that should/would be pulling any power, while the vehicle is turned off.

When I do the above test.... So far using only a test light, and not a voltmeter... If I leave it disconnected for a bit, then when I touch the probe to the battery post, I get a small bit of sparks at contact, and then the light comes on very dim. Stays on for maybe 15 seconds, then slowly goes completely out.

Is this "normal" for an aftermarket radio ?

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Ok, wait. I'll go back out and test with a voltmenter, now.

Ok, with the voltmeter, it is a constant 12 volts. Always.

But... Hook the test light up. Test from the end of the test light... The light doesn't come on, voltage stays at 12v.

Take the positive lead from the meter away from the test light. Touch the test light directly to the battery post. The light comes on very very dim. About 5 seconds at the most. The goes out abrubtly.

Take the test light probe away from the battery post and touch the meter probe to it directly, again, and the reading is very very low, but steadily/slowly climbs again.

Ok, one last test I want to do. I'll disconnect the radio fuse and see if that turns the radio off. But that still wouldn't cut off the 'always on' portion of the radio, would it ?

Let's find out. Guess I'm going to have to pull the radio out to get to it's wiring...

My goal here is to get to a point where there is zero draw with the vehicle off. Then I can start reattaching things, and see what is what...
 

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Discussion Starter · #2 ·
Using the amps part of the volt-ohmeter...

When you first touch the probe to the battery post, it jumps off the scale. Then it immediately settles down to about .25 milliamps, or whatever that reading is on the meter. LOL

Next up, pulling the radio.
 

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Maybe a capacitor draining?
 

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Discussion Starter · #4 ·
BigSwede said:
Maybe a capacitor draining?
Makes sense. But with the negative cable disconnected from the battery, where is the capacitor getting it's power, to 'recharge' ?

Because it happens after you leave things disconnected for a while.

I was thinking it was more like a capacitor re-charging itself every time it gets reconnected. Then slowly letting off the amperage draw, after it gets charged. Which only takes a few seconds. But continues with that miniscule amperage draw forever, after it is recharged.

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With the radio main fuse, (in it's own wiring harness), removed, the amp meter shows only about .07 amps still being drawn.

And the test light never lights up when touched to the battery post.

Stiiiiiillll something causing that tiny drain, though. (10 volts, .05 to .07 milliamps) Gotta find it.
 

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is the truck fuel injected if so the computer stays active for 20 mins then goes into a stand by mode for like and hour or so if you cut the power to it then reconnect it it checks every sensor "with an are you there" milli amp signal
 

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Discussion Starter · #6 ·
Ghost said:
is the truck fuel injected if so the computer stays active for 20 mins then goes into a stand by mode for like and hour or so if you cut the power to it then reconnect it it checks every sensor "with an are you there" milli amp signal
Aha ! I wondered if that was what was going on.

Ok, I just took my insulin. So I gotta eat.

Next time I go out, I'll disconnect the ecu, and see what happens.

Thank you !
 

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Discussion Starter · #7 ·
Ok, I couldn't stand it anymore. I ran out there and disconnected the ecu, and tested again.

Absolutely no draw, whatever.

So now I have my baseline, and can start hooking things back up.

I'm thinking the minor draw from the radio presets, and the ecu would take a couple months at least, to drain the battery.

So now the hunt is on, for what drained the battery.
 

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Discussion Starter · #9 ·
bradzuzu said:
An alternator with diodes going out can drain your thang !!!! Lol
Just sayin.....:)
Well, that fits with my earlier alternator theory.

We'll see.

It got too dark and cold, and I quit for the night.

I may get too frustrated later, with sitting around thinking about it and go out there with a jacket and flashlight, though. LOL
 

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Discussion Starter · #12 ·
bradzuzu said:
What's the verdict ??? Did you have to put her down ???
So far I have determined how to get to a complete 'no-drain' situation.

From there, I have been testing the individual systems.

I have found that there is a problem in the power window circuits. That is what drained the battery.

Those will now be put on a relay, and possibly a master switch that will have to be flipped before you can use the windows. (Thought about just wiring them to an ignition-on power source. And decided that if they are indeed grounding out somewhere, I don't want that drain on the system, even when the engine is running.) Not a big inconvenience for me. Not like I constantly open and close the windows.

Still going to try to track down the exact cause of the problem in that circuit. Just need to get on to other things, first.

The lock circuit is pefect. No problems there. I'll wire that straight through with a 20 or 25 amp fuse.

I won't know about the alternator until I have everything worked out, and back together. Then I'll test the alt.
 

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Doe your vehicle have a Retained Accessory Power (RAP) relay? They will "pull" a little power for about 20 minutes or so after the key is turned to the off position. They will then reactivate upon opening of the door. These can go bad and suck the battery down though most of the time they go bad in the open circuit mode.
 

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Discussion Starter · #14 ·
shooter said:
Doe your vehicle have a Retained Accessory Power (RAP) relay? They will "pull" a little power for about 20 minutes or so after the key is turned to the off position. They will then reactivate upon opening of the door. These can go bad and suck the battery down though most of the time they go bad in the open circuit mode.
I don't believe so.

The tiny drain that was so elusive was the ecu. Unplug that, and there is no drain whatsoever.
 

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You don't also have an additional tiny drain for your stereo?
 

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It sounds like a pain in the butt!!! Did this start after the wet weather ??? Maybe a relay is partially coroded and seeking ground/power ??? Does your fues box have a couple little diode's???
 

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Discussion Starter · #18 ·
Not at all a pain in the butt. I enjoy the challenge of electrical work.

Already dealt with the drain problem. See above.

A problem developed in the power windows. Maybe water got inside a door and is grounding out one of the motors. I really don't know at this point.

Won't know about the alt until later.
 

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I read through, but I think the diodes not positive but I think they control voltage going to some of your appendages. And or relays. Maybe it's just poop ah ganda ???? :)
 

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Discussion Starter · #20 ·
bradzuzu said:
I read through, but I think the diodes not positive but I think they control voltage going to some of your appendages. And or relays. Maybe it's just poop ah ganda ???? :)
I don't know about any diodes.

If they were there, they'd probably be underneath the fuse box, and i am not going to pull that, at this time.

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Well, I got the lock system, and my "upgraded" blower system all wired up, and still no drain.

So far, so good.

My goal to get done before the end of day today, is to get the power windows set up with a master switch and relay.

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Like I said earlier, I enjoy the challenge of electrical work. It's not a pain in the butt.

I should say, I enjoy the work, when it is hands-on. I have to use my brain and my hands. That is always enjoyable.

I don't so much enjoy it when it is all brain-work. Sitting around trying to figure out a system that I can't actually get my hands on, can be a pain in the butt.

I can trace and diagnose a circuit, completely in my head. No problem. It is all logical.

But when it is someone else who is doing the actual work, there are so many ways they can think they know what I said, and end up not at all doing what I suggested... Then insisting they did... Etc...AAARRGGHHHHH
 
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