Battery Drain from battery fuse/fusible link

[Chevy416ci]

Hey guys,

I'm hoping some of you might be able to help me or point me in the right direction here.

2015 Camaro SS(Vin W)/ 6-speed / CAI / Coilovers / mini-starter

I have an oscillating 3-5amp battery drain coming from the battery fuse area.

First thing I did was have my battery tested which ended up having a bad cell, so I bought a new battery.

I replaced my starter a few months ago, so that was the next thing i checked thinking that it had a bad connection. But the connections were flush, tight and nothing looked out of the ordinary. However, I removed the power and signal wire from the starter to verify, still had the drain. I also checked the voltage at the battery when starting the car and it never dropped under 11 volts.

I proceeded to disconnect both the pin connector and power wire from the alternator, still had the drain. I have reason to believe that i have a bad diode as well... which might be part of the issue. I used the diode setting on my meter, red lead to the power pole and black lead to the housing and had a reading around 400. I reversed the leads and also had a reading around 400-500.

Next I pulled every fuse/relay from all 3 fuse blocks to no avail, STILL had a 3-5amp drain.

In an attempt to isolate both the starter and alternator, i completely disconnected the positive jumper pole in the engine bay. Still had the drain..

I scoured the internet and came across this battery fuse post, and come to think, i have this black box connected to the side of my power cable.
https://www.camaro5.com/forums/showthread.php?t=376496
So i removed the black box, retested the drain and sure enough it went down to 0.11 amps on the 10amp scale.

My thought is that if the battery fuses and/or fuse links(are they actually fuse links that connect to the battery fuse, or just larger wires?) are burnt out, i wouldn't have a drain because the circuit would technically be open, correct? The battery fuse doesn't look burnt or blown out. So what are these 2 circuits coming from the battery fuse supporting? Alternator... and what else? What is pulling 3-5 amps, especially if the starter and alternator have been disconnected?

Does anyone have an electrical diagram to give me a visual of what is on these 2 circuits. Any tips on how or what to test to isolate and fix this issue?

[AlanRubin]

Your drain is not at the fusible links.

You have another fuse box at the rear right side of the car.

You cannot have a drain without a ground at the other side of it, so it cannot be
the fusible links.

3A drain is high, and usually means a bad alternator....

Disconnecting the black box, eliminates power to the rear right fuse box in the trunk.
IF the drain went down to .11 after that, you need to trace out those two wires,
the 100A and 60A to where they go and troubleshoot there.

[Chevy416ci]

Originally Posted by AlanRubin

Your drain is not at the fusible links.

You have another fuse box at the rear right side of the car.

You cannot have a drain without a ground at the other side of it, so it cannot be
the fusible links.

3A drain is high, and usually means a bad alternator....

Disconnecting the black box, eliminates power to the rear right fuse box in the trunk.
IF the drain went down to .11 after that, you need to trace out those two wires,
the 100A and 60A to where they go and troubleshoot there.

I have checked the rear right fuse box in the trunk, pulled all fuses and relays and still had the drain, also the other 2 fuse boxes (dash/engine bay). Also completely disconnected the alternator, which I still assume has a bad diode and will replace, but if the Alt isn't draining my battery then it doesn't make sense to put a new Alt in just yet until I can find the source of the drain. Been having intermittent issues, such as passenger window not working then working, radio not working then working, passenger air bag on with no passenger then back off again when i restart the car. Possible the BCM is the issue? I do realize i will need to trace the two wires from the black box, just trying to narrow down the possibilities before i tear my car apart to trace the wires from start to finish.

[gtstorey]

It sounds like you have a chaffed wire that is making just enough connection to draw a load but not enough to blow a fuse.

[Chevy416ci]

Thank you for the input, I do appreciate it. I double checked my fuses again just to be sure I didn't miss anything, and the Radio fuse in the trunk drops the drain by 1 amp, not the full 3-5 amps.

Next step is to chase down those 2 wires from the battery as you guys have mentioned. I've had a lot going on lately and not enough time to do it yet, so i've had to unplug my battery everytime I turn the car off.. PITA

I will report back once I am able to track this down.

[Mouse330]

Do a search for
Testing Parasitic Draw via Fuse Voltage Drop

[AlanRubin]

Pull the front power/starter/alt/fusebox cable off the jumper post.
Pull the 60A wire, and the 100A wire at the battery.


This means NO power to any of the car's components.

If you still have a draw, then it's the main power cable that runs from the
battery, to the post, or at the interior fuse box, SOMEWHERE.

Once you have pulled all three of those, all that is left is the interior
fuse box, and anything that runs off it.

[Roader]

I’m right there with you. Just replaced battery and alternator and still having issues. I’m starting at day 1 here so if you find anything let me know so I can double check it as well