Parasitic Draw
August 4th, 2022, 5:55 PM
#1
Parasitic Draw
I have a 2009 GMC Sierra 1500 SLT. With radio plugged in I’m drawing 3.5 amps through meter in series with battery. I removed the radio and got it down to 1.6, but the only way I can get it to .001 milliamperes is to pull 8 fuses as followed, Lbec 1, and Lbec 2, instrument panel cluster, airbag system battery, climate control battery, key ignition theft, Audio system, and fuel system control module. Any guidance as to what my root cause of all the amp draw would be appreciated. I went through 2 batteries in a couple weeks so I’ve ruled out bad batteries after seeing how much amp draw I was getting.
February 22nd, 2023, 5:20 PM
#2
Sam, not sure if you came up with a resolution to your problem or not. I am quite knowledgeable in this area and have some suggestions. But being this thread is a few months old, I won't post unless you or someone else posts.
Thanks
Mike
Thanks
Mike
February 22nd, 2023, 5:34 PM
#3
February 22nd, 2023, 6:02 PM
#4
Well, you mentioned in order to get rid of the 1.6 amps is to pull out a lot of fuses. Do ALL of those fuses have to be pulled or did you narrow it down to one in particular? Does pulling each one, one at a time lower the draw. I.e. does it go from 1.6 amps to 1.4, then to 1.2 when you pull another fuse, and so on until it's down to minimal?
On these series trucks, there are 3 MAIN ground wires and 3 MAIN positive wires from the battery. The grounds have 2 from the negative battery terminal. One (The thicker) goes to the engine block. This is necessary because motors sit on motor mounts to provide cushion. Without them your motor would break off of it's mount on the first big bump. But as such, these motor mounts are non-conductive. E.g. rubber, neoprene, etc. So the engine block needs a ground. And being the alternator is attached to the engine block, this ground from the batter is very important. But it sound like this ground is probably doing ok; unless your alternator isn't charging your battery. But this doesn't seem to be the case. The 2nd ground goes from the battery to the frame/chassis of the vehicle. Usually up front under the radiator. You could trace it. But the real IMPORTANT ground is to the body of the vehicle. This is done usually with a braided ground strap from the back of the engine block. It goes to a ground lug on the firewall. This is how all your gauges, stereo, HVAC, and everything else you use in the vehicle gets it's ground. If a ground isn't good, then voltage goes down. When voltage goes down, amperage goes up. This is how electronics work. So, the first thing I'd do is ensure that ALL the ground are connected properly and are in good shape. Especially the braided ground strap from the back of the engine block to the firewall ground bolt. There another one right next to it to ground the hood. But the bolt with the braid to the engine block is super important.
Being you are getting a code mentioning the dimming circuit, it could be that circuit or the switch or even the switch sensors in the doors. This controls the dome lights and others. The easiest way to check would be to pull the dome light bulb and other interior light bulbs. Then measure the parasitic draw again. REMEMBER: When testing parasitic draw, newer vehicles do a lot of ON and OFF power for a timed period. E.g. you could show .004 ma draw, then OPEN and CLOSE the door and for the next minute or two it could show MUCH HIGHER draw. Also, if you're testing with a traditional volt meter where you have to disconnect the battery negative cable to put the volt/amp meter in series, this will also kick in voltage/amps for a couple of minutes until it goes back to sleep. (CLAMP on DC/AC Amp meters are the best to use. But if the bulbs don't lead you in the correct direction, the next thing would be to pop open the dash and disconnect the wiring from the dimmer switch. After each move, make sure the vehicle's doors are shut, let it wait, hood always open, and clamp test at the battery. I had to track down a parasitic draw a few weeks back. I manually turned off the interior lights from turning on when the doors are opened, left the doors open so I could get in and out, and let the voltage stabilize before testing. Found my parasitic draw to be a bad connection on the wiring from my 3rd break light assembly to the interior lights of my topper shell. Electrical problems can be a biotch.
Best of luck, keep us updated and ask questions if you have them.
Mike
On these series trucks, there are 3 MAIN ground wires and 3 MAIN positive wires from the battery. The grounds have 2 from the negative battery terminal. One (The thicker) goes to the engine block. This is necessary because motors sit on motor mounts to provide cushion. Without them your motor would break off of it's mount on the first big bump. But as such, these motor mounts are non-conductive. E.g. rubber, neoprene, etc. So the engine block needs a ground. And being the alternator is attached to the engine block, this ground from the batter is very important. But it sound like this ground is probably doing ok; unless your alternator isn't charging your battery. But this doesn't seem to be the case. The 2nd ground goes from the battery to the frame/chassis of the vehicle. Usually up front under the radiator. You could trace it. But the real IMPORTANT ground is to the body of the vehicle. This is done usually with a braided ground strap from the back of the engine block. It goes to a ground lug on the firewall. This is how all your gauges, stereo, HVAC, and everything else you use in the vehicle gets it's ground. If a ground isn't good, then voltage goes down. When voltage goes down, amperage goes up. This is how electronics work. So, the first thing I'd do is ensure that ALL the ground are connected properly and are in good shape. Especially the braided ground strap from the back of the engine block to the firewall ground bolt. There another one right next to it to ground the hood. But the bolt with the braid to the engine block is super important.
Being you are getting a code mentioning the dimming circuit, it could be that circuit or the switch or even the switch sensors in the doors. This controls the dome lights and others. The easiest way to check would be to pull the dome light bulb and other interior light bulbs. Then measure the parasitic draw again. REMEMBER: When testing parasitic draw, newer vehicles do a lot of ON and OFF power for a timed period. E.g. you could show .004 ma draw, then OPEN and CLOSE the door and for the next minute or two it could show MUCH HIGHER draw. Also, if you're testing with a traditional volt meter where you have to disconnect the battery negative cable to put the volt/amp meter in series, this will also kick in voltage/amps for a couple of minutes until it goes back to sleep. (CLAMP on DC/AC Amp meters are the best to use. But if the bulbs don't lead you in the correct direction, the next thing would be to pop open the dash and disconnect the wiring from the dimmer switch. After each move, make sure the vehicle's doors are shut, let it wait, hood always open, and clamp test at the battery. I had to track down a parasitic draw a few weeks back. I manually turned off the interior lights from turning on when the doors are opened, left the doors open so I could get in and out, and let the voltage stabilize before testing. Found my parasitic draw to be a bad connection on the wiring from my 3rd break light assembly to the interior lights of my topper shell. Electrical problems can be a biotch.
Best of luck, keep us updated and ask questions if you have them.
Mike
February 22nd, 2023, 6:12 PM
#5
Well, you mentioned in order to get rid of the 1.6 amps is to pull out a lot of fuses. Do ALL of those fuses have to be pulled or did you narrow it down to one in particular? Does pulling each one, one at a time lower the draw. I.e. does it go from 1.6 amps to 1.4, then to 1.2 when you pull another fuse, and so on until it's down to minimal?
On these series trucks, there are 3 MAIN ground wires and 3 MAIN positive wires from the battery. The grounds have 2 from the negative battery terminal. One (The thicker) goes to the engine block. This is necessary because motors sit on motor mounts to provide cushion. Without them your motor would break off of it's mount on the first big bump. But as such, these motor mounts are non-conductive. E.g. rubber, neoprene, etc. So the engine block needs a ground. And being the alternator is attached to the engine block, this ground from the batter is very important. But it sound like this ground is probably doing ok; unless your alternator isn't charging your battery. But this doesn't seem to be the case. The 2nd ground goes from the battery to the frame/chassis of the vehicle. Usually up front under the radiator. You could trace it. But the real IMPORTANT ground is to the body of the vehicle. This is done usually with a braided ground strap from the back of the engine block. It goes to a ground lug on the firewall. This is how all your gauges, stereo, HVAC, and everything else you use in the vehicle gets it's ground. If a ground isn't good, then voltage goes down. When voltage goes down, amperage goes up. This is how electronics work. So, the first thing I'd do is ensure that ALL the ground are connected properly and are in good shape. Especially the braided ground strap from the back of the engine block to the firewall ground bolt. There another one right next to it to ground the hood. But the bolt with the braid to the engine block is super important.
Being you are getting a code mentioning the dimming circuit, it could be that circuit or the switch or even the switch sensors in the doors. This controls the dome lights and others. The easiest way to check would be to pull the dome light bulb and other interior light bulbs. Then measure the parasitic draw again. REMEMBER: When testing parasitic draw, newer vehicles do a lot of ON and OFF power for a timed period. E.g. you could show .004 ma draw, then OPEN and CLOSE the door and for the next minute or two it could show MUCH HIGHER draw. Also, if you're testing with a traditional volt meter where you have to disconnect the battery negative cable to put the volt/amp meter in series, this will also kick in voltage/amps for a couple of minutes until it goes back to sleep. (CLAMP on DC/AC Amp meters are the best to use. But if the bulbs don't lead you in the correct direction, the next thing would be to pop open the dash and disconnect the wiring from the dimmer switch. After each move, make sure the vehicle's doors are shut, let it wait, hood always open, and clamp test at the battery. I had to track down a parasitic draw a few weeks back. I manually turned off the interior lights from turning on when the doors are opened, left the doors open so I could get in and out, and let the voltage stabilize before testing. Found my parasitic draw to be a bad connection on the wiring from my 3rd break light assembly to the interior lights of my topper shell. Electrical problems can be a biotch.
Best of luck, keep us updated and ask questions if you have them.
Mike
On these series trucks, there are 3 MAIN ground wires and 3 MAIN positive wires from the battery. The grounds have 2 from the negative battery terminal. One (The thicker) goes to the engine block. This is necessary because motors sit on motor mounts to provide cushion. Without them your motor would break off of it's mount on the first big bump. But as such, these motor mounts are non-conductive. E.g. rubber, neoprene, etc. So the engine block needs a ground. And being the alternator is attached to the engine block, this ground from the batter is very important. But it sound like this ground is probably doing ok; unless your alternator isn't charging your battery. But this doesn't seem to be the case. The 2nd ground goes from the battery to the frame/chassis of the vehicle. Usually up front under the radiator. You could trace it. But the real IMPORTANT ground is to the body of the vehicle. This is done usually with a braided ground strap from the back of the engine block. It goes to a ground lug on the firewall. This is how all your gauges, stereo, HVAC, and everything else you use in the vehicle gets it's ground. If a ground isn't good, then voltage goes down. When voltage goes down, amperage goes up. This is how electronics work. So, the first thing I'd do is ensure that ALL the ground are connected properly and are in good shape. Especially the braided ground strap from the back of the engine block to the firewall ground bolt. There another one right next to it to ground the hood. But the bolt with the braid to the engine block is super important.
Being you are getting a code mentioning the dimming circuit, it could be that circuit or the switch or even the switch sensors in the doors. This controls the dome lights and others. The easiest way to check would be to pull the dome light bulb and other interior light bulbs. Then measure the parasitic draw again. REMEMBER: When testing parasitic draw, newer vehicles do a lot of ON and OFF power for a timed period. E.g. you could show .004 ma draw, then OPEN and CLOSE the door and for the next minute or two it could show MUCH HIGHER draw. Also, if you're testing with a traditional volt meter where you have to disconnect the battery negative cable to put the volt/amp meter in series, this will also kick in voltage/amps for a couple of minutes until it goes back to sleep. (CLAMP on DC/AC Amp meters are the best to use. But if the bulbs don't lead you in the correct direction, the next thing would be to pop open the dash and disconnect the wiring from the dimmer switch. After each move, make sure the vehicle's doors are shut, let it wait, hood always open, and clamp test at the battery. I had to track down a parasitic draw a few weeks back. I manually turned off the interior lights from turning on when the doors are opened, left the doors open so I could get in and out, and let the voltage stabilize before testing. Found my parasitic draw to be a bad connection on the wiring from my 3rd break light assembly to the interior lights of my topper shell. Electrical problems can be a biotch.
Best of luck, keep us updated and ask questions if you have them.
Mike
I forgot to tell you the lights to the 2 drop down visors on the interior didn’t work so I need to investigate that more
February 23rd, 2023, 5:50 PM
#6
Do you have any suggestions on what to do to fix the 2 vanity lights if I’ve already confirmed continuity between the 12v power wires, and the neutrals to the lights, that go to the bcm?
February 23rd, 2023, 9:10 PM
#7
When you say that there is continuity between the 12 power wires AND the neutrals to the light; are you saying that the wires are shorted? If they are, then that could definitely be the current draw you're seeing and is killing the battery. Or are you saying that the continuity of the 12v wire and BCM is good, and the continuity of the neutral (ground) wire is good. In which case, the bulbs would/should work and light up.
With automotive lights, like with any lights, one side of the bulb goes to the 12v power. The other side of the bulb usually goes to the on/off switch and from there to ground. When the switch is on, the ground is connected, the circuit is completed, and the light bulb lights. (In some designs, they will put the switch on the 12v wire so the ground is connected all the time and the 12v goes through the on/off switch).
With automotive lights, like with any lights, one side of the bulb goes to the 12v power. The other side of the bulb usually goes to the on/off switch and from there to ground. When the switch is on, the ground is connected, the circuit is completed, and the light bulb lights. (In some designs, they will put the switch on the 12v wire so the ground is connected all the time and the 12v goes through the on/off switch).
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February 24th, 2023, 6:49 AM
#8
When you say that there is continuity between the 12 power wires AND the neutrals to the light; are you saying that the wires are shorted? If they are, then that could definitely be the current draw you're seeing and is killing the battery. Or are you saying that the continuity of the 12v wire and BCM is good, and the continuity of the neutral (ground) wire is good. In which case, the bulbs would/should work and light up.
With automotive lights, like with any lights, one side of the bulb goes to the 12v power. The other side of the bulb usually goes to the on/off switch and from there to ground. When the switch is on, the ground is connected, the circuit is completed, and the light bulb lights. (In some designs, they will put the switch on the 12v wire so the ground is connected all the time and the 12v goes through the on/off switch).
With automotive lights, like with any lights, one side of the bulb goes to the 12v power. The other side of the bulb usually goes to the on/off switch and from there to ground. When the switch is on, the ground is connected, the circuit is completed, and the light bulb lights. (In some designs, they will put the switch on the 12v wire so the ground is connected all the time and the 12v goes through the on/off switch).
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