For the last month, Ive had issues with my Blazer not wanting to start without a jump... I figured dead cell in the battery, so I replaced it. Now my new battery is losing charge as well. My alternator is working fine, as I had it tested. I have a nice system, and it's all hooked up properly. The amp does not stay on when I turn off the truck. So I dont believe its that. I have not spotted any loose grounds, or worn wires, and the truck runs fine when started, no missing, or other issues, so Im at a loss to explain the drain. Anyhow, someone mentioned an issue with the alternator, where a diode gets stuck, and can pull from the battery even when the truck is off... Has anyone experienced this here? Is this a repairable issue, or do I have to replace the alt completely? As previously stated, the alternator is charging properly. I can drive it all day long, and its fine. But the next morning, the battery has less than 11 volts, and is a bitch to crank. Im up for suggestions, thanx.

Also, I have a fairly thick blue/white wire that comes up from beneath the brake booster that has been cut... What does it hook up to?

 

You first have to determine where the current draw is coming from. Plenty of threads on that here... You need to isolate the circuits and test. If you have over a 35mA draw at the battery, there is something that is pulling current even with the key off. Start by pulling out all of your fuses and putting them in one at a time, with only one fuse installed each time.

 

I know my stereo pulls b/c of its memory. But that was never a problem before this started happening. I was told the ecu and one more things pulls as well. Do you mean to pull all fuses and do a test with each fuse I reinsert? Would that test be conducted @ the battery?
Sorry for my ignorance in such matters, although I love working on cars, and can do quite a bit... Except electrical issues... So thanks for the response.
ALSO, I still have no clue as to the origin of this thick blue/white wire coming from underneath the brake booster. I guess this means Im no good for electrical diagrams either. Not that I have one that is... lol Maybe a picture would help you to identify the wire?

Heres the wire I can't identify:

http://i2.photobucket.com/albums/y37...w/100_7120.jpg

Heres my battery set up. Nice and proper.

http://i2.photobucket.com/albums/y37...w/100_7121.jpg

Ground wires secured to the plenum. (Not loose)

http://i2.photobucket.com/albums/y37...w/100_7124.jpg

Battery ground is secured to the passenger manifold. (Not loose)

http://i2.photobucket.com/albums/y37...w/100_7125.jpg

I have my amp remote wire tied into my wiper fuse...

 

One quick way to see if you've got a drain is to make sure everything that draws power is off, ie: doors closed, int. lights off, keys out, etc. then at night or in a dark place take off the neg. cable from the battery and just touch it to the terminal. there will be a minute draw from the ecu and stereo memory but if it's a spark that jumps to the terminal there's a short somewhere. I had the same problem a while back, turns out my battery died in the last cold snap but with the new one installed I did the test and there was no spark jump at all so following that logic, any spark = a short. After that it's hit and miss to find it. As mentioned above, get out the meter and start pulling fuses one by one. Good luck....elec. problems are one of the hardest things to track down.

 

That may work on a vehicle this old, however, I believe that even the OBD1 computers have a higher current draw when first powered up, then it drops down.

To the OP, I like to leave the multimeter installed inline with the negative battery terminal, black lead on the battery, red lead on the battery cable. Then install only one fuse at a time, working through all of the locations. If you get a high initial current draw, keep the fuse in and check it in 3-5 minutes to see if it has decreased. Write down all of the locations with an abnormally high reading and let us know what they are. Do not forget to also do this with any addon circuits you or previous owners have installed.

 

I may have found the problem, but won't know if it's solved until tomorrow morning when I try to start it. I found the + cable to the amp from the battery laid up on the manifold. I'm thinking that have been the issue. So far, after repeated checks throughout the day, the volt meter still reads 12v. I won't know until tomorrow morning. If it loses charge then I will follow the procedures to test a fuse at a time. I'll update in the morning... Thanks.
Also, still no clue on what the b/w wire is??? I'd really like to know. And btw, the motor was a transplant before I bought the truck. I have no complaints as I love my truck! :P Thanx for the help guys.

 

This morning I turned the key, and saw that it still had 12v. It started, a little hard, but it started. Anyhow, I guess I will continue to see if it starts with no problem as the days go by. I'm hoping the power wire I found melted to the header was the cause of the drain.