Trying to diagnose a parasitic draw

[eddiec]

DIY'er here: I am trying to determine the amp draw during a parasitic drain test on my 2005 GMC Envoy. Other vehicles I've tested the draw is generally pretty stable....not so much here. Starts out at about 3.8 amps and then ends up dropping down to about 0.30. As it's all over the place, what's the real draw....the beginning or the end? The battery goes dead if it sits more than 48 hours. Here's a 50 second You Tube video of the meter:

Any help would be appreciated.

 

[DPG]

Bear in mind that modern vehicles shut down in various stages. Sometimes it can take 15 minutes or more to get to the minimum level.

 

[newfutile]

As dpg says the computers / modules go to sleep in stages , if after 20 mins you have more than a few milliamps pull fuses one at a time till you see what’s drawing the current,

 

[mainline]

DIY'er here: I am trying to determine the amp draw during a parasitic drain test on my 2005 GMC Envoy. Other vehicles I've tested the draw is generally pretty stable....not so much here. Starts out at about 3.8 amps and then ends up dropping down to about 0.30. As it's all over the place, what's the real draw....the beginning or the end? The battery goes dead if it sits more than 48 hours. Here's a 50 second You Tube video of the meter:

Any help would be appreciated.

Radios and alarms are notorious for it on some cars.
But there are a lot of other things like alternator or any of the modules ... just unplug fuses / modules to narrow it down.

 

[Eddy Currents]

Firstly, In your video, 21 seconds in, Did you fart?

When trying to measure parasitic drain it is vital to either make sure everything on the car is closed or fooled into being closed. All doors, boot, bonnet, glove box switches and obviously all lights, radio etc. off

Then the cars modules will start to go to sleep, which as others have said above can take quite a while. And if you open a door or do anything then it wakes up again

It will jump all the place as things are shutting down until you get a final stable figure which is your drain, although some modern cars have a small amount as normal

As a couple of people have said above the next step is to see what is causing it but I think pulling fuses is the wrong thing to do because this often wakes a module up and you have to go through the whole shutdown wait again

The easiest way is to measure voltage drop across the fuses while they are still in place
If there is current flowing through the fuse then you will see voltage drop in the mV range. You can then see what that fuse is for

 

[mainline]

Firstly, In your video, 21 seconds in, Did you fart?

When trying to measure parasitic drain it is vital to either make sure everything on the car is closed or fooled into being closed. All doors, boot, bonnet, glove box switches and obviously all lights, radio etc. off

Then the cars modules will start to go to sleep, which as others have said above can take quite a while. And if you open a door or do anything then it wakes up again

It will jump all the place as things are shutting down until you get a final stable figure which is your drain, although some modern cars have a small amount as normal

As a couple of people have said above the next step is to see what is causing it but I think pulling fuses is the wrong thing to do because this often wakes a module up and you have to go through the whole shutdown wait again

The easiest way is to measure voltage drop across the fuses while they are still in place
If there is current flowing through the fuse then you will see voltage drop in the mV range. You can then see what that fuse is for

I find a clamp meter is easier, and then pull fuses and leave them out as you go along.
The average car is about 50ma or less, sometimes it's not that simple to narrow down, especially when it's in the fusebox itself.
But each to their own as long as the end result is a fix.