Help with an electrical draw

[73431Cutlass]

Hey,
I got a question on a newer car with a very large draw. Its a 2001 Chevy Impala. It can draw a fully charged battery down in 2 to 3 days. I havea dumb question also on reading an amp meter. I set it up on 20aAC and it reads anywhere from 1.55 to 1.93 to 2.4 or .03. I tried to set it on ma but I get no readings.
My question is anyone on here a GM mechanic or know of anyone who is that might be able to help with somepointers? I think I narrowed it down to the BCM module, but that module controls a large amount of things. Once unplugged I get NO draws at all, I should get something, right? I was gonna turn it around real fast for a good profit but I like the car and want to keep it, problem is I have 4 cars and I drive my work truck more and my cars sit and look pretty. Well now mostly tucked away in a warm garage for the cold months....
Thanks Steve

[ragz442]

You need to make sure you have the leads connected to the proper jacks on the meter, check the manual for ampers [if you have one]. Disconnect the negative battery cable and hook one lead to the battery and the other to the cable [in series] with the meter in dc amp scale. You also have to make sure the fuse is good in the meter, if someone hooked it up to check voltage with the leads in the amp position on the meter, it will blow the fuse. You shouldn't have more than a 30 mili amp draw [0.03]. You need to let the modules "time out" for about 15 minutes, if you have more than the normal draw, start pulling fuses one at a time until the draw is gone, to pinpoint circuit. Kinda hard to explain on the computer, good luck.

[73431Cutlass]

Thats what I have been doing... Its funny that out of 3 GM techs none of them really know how to test for a draw in milliamps. I found the left bank/side fuse panel to have the draw and looks like it is the BCM circuit. Problem is that the circuit controls a large number of things in the car, Body Control Module. With that main fuse pulled I have no draw at all, if it is in the draw bounces up and down, like something is "waking up" and then settles. What ever it is it is drawing what looks like to me to be a 1.55 amp draw sitting. If I pull fuses that are related to the BCM in a way but also attached to something else the draw stays, like BCM/PCM, or BCM/cluster. Thats why I was asking, not really sure if I replace the BCM will itfix it. The BCM is known to go bad and are very delicate with power surges. The hard part is it is a dealer part only and it has to be installed by the dealer, it needs the VIN burned in and you have to re learn the theft system and also install some GM updates etc..... God only knows the current labor rate at GM, plus 200. or so part. Thats why I am hesitant to just go and replace it. I am ready to pull my hair out on this one....

[gow589]

Just curious, I am not sure what you are measuring with. I was just measuring mine with a meter used for R/C hobbies. Some one had previously put a relay on the power antenna and it was constantly pulling power. Just to make sure I got it right, I hooked up the the power meter. It sowed xxx watts and something like 18mah's.

After messing with it for a minute, I realized the MAH were accumulative and not the current draw. It was just showing how much current had been used. Once the door was closed, the light was off, the MAH did not move and the rest was showing zero.

[ragz442]

Thats what I have been doing... Its funny that out of 3 GM techs none of them really know how to test for a draw in milliamps. I found the left bank/side fuse panel to have the draw and looks like it is the BCM circuit. Problem is that the circuit controls a large number of things in the car, Body Control Module. With that main fuse pulled I have no draw at all, if it is in the draw bounces up and down, like something is "waking up" and then settles. What ever it is it is drawing what looks like to me to be a 1.55 amp draw sitting. If I pull fuses that are related to the BCM in a way but also attached to something else the draw stays, like BCM/PCM, or BCM/cluster. Thats why I was asking, not really sure if I replace the BCM will itfix it. The BCM is known to go bad and are very delicate with power surges. The hard part is it is a dealer part only and it has to be installed by the dealer, it needs the VIN burned in and you have to re learn the theft system and also install some GM updates etc..... God only knows the current labor rate at GM, plus 200. or so part. Thats why I am hesitant to just go and replace it. I am ready to pull my hair out on this one....

Steve, are you waiting a while to see if the draw goes away after the module times out? Your gonna get that fluctuation until the module goes to sleep.

[73431Cutlass]

It does this 24/7..... I was told to wait 20 minutes up to an hour and recheck. Still does it, so I bite the bullet today and ordered a BCM from GM. Now I have to prepair myself for the bill from the dealership to programm it.