Weird battery problem...

[crw]

Originally Posted By: oppirs
Originally Posted By: crw
Tomorrow I'll take the alternator out and have it tested. This site is great! Thanks.


I've dealt with dead new batteries on 2 GMC's, 1 Suburban. 2000 -2004. Takes about 3-5 days to drain the battery, DEAD, if not run. It's was a 2.4 amp draw from the radio circuit.

Keys out, pull radio fuse, test for draw. Fix was to buy aftermaket radios and cancel/remove OnStar. Or pull fuse until your ready to use the truck. If alt tests out good, hoped that helped. Good luck!


Thanks, I'll look there if the alternator comes back clean.

 

[JimPghPA]

Now days the ignition, fuel pump, computer, and everything else draws so much current that the alternator does not have much to spare. It is easy to cook the winding in a good alternator by using a good battery that is not charged. By the time the alternator get the battey charged to the point that is is not using extra current to charge it, the alternator is damaged.

The wise thing to do is to bring the battery up to 80 percent with a charger before you put it in the vehicle.

 

[oppirs]

Originally Posted By: JimPghPA
Now days the ignition, fuel pump, computer, and everything else draws so much current that the alternator does not have much to spare. It is easy to cook the winding in a good alternator by using a good battery that is not charged. By the time the alternator get the battey charged to the point that is is not using extra current to charge it, the alternator is damaged.

The wise thing to do is to bring the battery up to 80 percent with a charger before you put it in the vehicle.


I'll help as needed. Xpect nothing more

 

[oppirs]

 

[crw]

OK, so the alternator comes out clean. I did a static draw test and found only about 6mA being drawn, which is normal. I guess I'm back to wait and see mode.

 

[crw]

Wow..........

Last night I had it all buttoned up, static draw test was 6mA, looking good. Today, it's dead again. The vehicle was not running during that time.

Simple question... if I have the amp meter in 200mA mode, the number reported would be in milliamps, correct? So it reports about 6mA. That should be fine. Now I'm really at a loss...

 

[oppirs]

What year is it? I use the 20amp setting on my DMV. One GMC would mild spark when touching the (-) and activate the solinode for the 4x4. Some how related to the radio, weird. Once the Delco/OnStar radio was remove, problem fixed.

One day drain it too fast. Were you fully charged? Batteries hate being in full dis-charge. Get it replaced. Did you test drive it, after install? This is hard from the internet.

 

[crw]

Originally Posted By: oppirs
What year is it? I use the 20amp setting on my DMV. One GMC would mild spark when touching the (-) and activate the solinode for the 4x4. Some how related to the radio, weird. Once the Delco/OnStar radio was remove, problem fixed.

One day drain it too fast. Were you fully charged? Batteries hate being in full dis-charge. Get it replaced. Did you test drive it, after install? This is hard from the internet.


Last night I installed it, ran it, just in the driveway. While running the voltage out was good. Then I shut it down, pulled the positive battery cable and did a current draw test. I was expecting a high draw, but didn't find it. Then I said, well, lets wait a few days and see what happens. Then this morning, totally dead again. I'm at work, the car is at home with the wife. I think she likes this, she gets to take my BWM when the Suburban doesn't work. The battery was fully charged when I put it back in.

 

[crw]

Guess what? I think it's the radio as opplrs mentioned. I repeated the static current measurement but this time in 10A mode (Doh!) and now I get about 10 AMPS being drawn while the car is off! Then I yanked the radio fuse, and the current goes way down into the milliamp range. I'll feel better if it starts in the morning!

 

[crw]

Where is my grumpy face?

So now I have no radio, but I also have no tach, speedometer, odometer, or fuel guage.

I just pulled the 15 A fuse labeled radio. So how do I know which of these circuits is the problem?

 

[oppirs]

I think their all run by that fuse. I know a hassle but put in the fuse before driving off & pull it when back home. 10 amps is large load don't leave that fuse in too long!

I just buy a nice usb mp3 radio from Crutchfields w/ all the wiring and call it a day. Much better than Delco but no OnStar you lose that feature.

 

[crw]

Yeah, I may have to assume it is the radio. I don't have OnStar. I guess technically, it could be the gas gauge or any of the other gauges that are now off. But OK, I think I may just take it to a local shop and have them put a cheap radio that fits in and hope that that solves it.

 

[TFB1]

Dunno about GM, but the "memory" circuit is a common problem with the Ford radios, I'd pull it out and recheck current draw...

 

[Vikas]

You obviously need to find out which specific circuit is the culprit. Assuming taking off the radio is not very painful, just take the radio off and check the drain again.

Otherwise, time to buy nifty inductive tool which will let you find the short without cutting the wire. The tool might be in $100 range but I bet it will cost you at least that much if you took the vehicle to a dealer.

- Vikas

 

[crw]

Wellll......

Dear Abby,

I thought my problem was solved. Then the battery drained overnight with the fuse out. Then I put my truck battery in it, and it drained it in 20 minutes. Is there any hope for me?

Sincerely, Hopeless in Pocatello

 

[crw]

Seriously, I think the next step is to disconnect the line to the alternator, then see if the battery stays charged while otherwise connected in the car.

 

[Corvette Owner]

Do you have lights in your sunvisors? Check them when dark, to see if they stay on.

Also, do you have electric adjustable seats? Another problem with some GM cars.

Good luck, it sure is a bumber.

 

[crw]

I ran home at lunch to work on the problem. I get a solid 9 to 10A draw with the battery connected. I pulled a dozen fuses, no change. I also disconnected the line to the alternator, no luck. No electric seats... not sure on the lights in sunvisors, will check. I guess I'll methodically pull each fuse, and also check the cable to the starter.

Corvette_Owner, I want to be one.

 

[crw]

OK, for those who are still following this saga, I have some interesting data.

My static draw of current was about 10A. If I pull the monster 50A fuse for RAP #1, the current draw goes down to 1.5A. RAP stands for Retained Accessory Power, and I guess it provides power to circuits that stay on when the key is off, like the radio.

If also pull the radio fuse, then the current drops to 0.06A. Of course, the radio fuse also controls the fuel gauge, PRNDL display, speedometer, odometer, and tach.

So I think I'm back to the radio. Any ideas? I google'd it, and the RAP is spoken of on some Chevy boards, but those threads drift off without any solid resolution. (I hate that!)

 

[oppirs]

I just know of the 2.4 amp draw via radio. Actives servos for 4x4. 10 amps sumthin' more.

What year of Sub is this???? Only dealt w/OnStar radio issues.