[Colt Hero]

Bring the Battery to AutoZone or Advance - loose. Let them Charge it up (maybe even overnight), and Load Test it. If it Charges up OK, and Load Tests OK ... then it's OK ... and the problem is your vehicle is draining it.

And you don't have to go to the Dealer to find the parasitic drain. If you don't know a good Independent Mechanic, ask some friends or co-workers where they go.

Or - here's another idea: does your area have a Vocational-Technical High School or Technical College? They have an Auto Repair Shop that'll do repairs for a small donation ... but you'll probably have to schedule an appointment...

 

[Colt Hero]

Some thoughts/ideas:

1.) If you don't already own one, probably a good excuse to go buy one of those Lithium Battery Jumpers. I bought the "Viking" at Harbor Freight. Fits in the glove box. Works well. In fact, I once used it for a whole week, twice a day, jump-starting my Equinox Battery every morning and night (at work) because I didn't want to be bothered buying a new Battery during the work week!

2.) Is this Battery Drain problem unique to the Terrain? And if so, is there a feature of the Terrain that is unique to the Terrain (i.e.: wasn't offered on the Equinox) that could be causing the Drain?

3.) Maybe guess it has something to do with OnStar and disable that by pulling a fuse?

4.) My Harbor Freight OBD-2 Code Reader (~$90) can log real-time data while driving. One item in the List is "Control Module Voltage" ... which I think is the Battery Voltage. There are other products out there (like ScanGuage) that plug directly into the OBD-2 Port and have a local LCD display of OBD-2 values. With ScanGauge, you could see the Battery Voltage real-time while driving, which means you could charge the Battery up, pull a fuse, then drive and watch to see if your Voltage is still dropping.

5.) Are you absolutely sure it's not your Alternator? Maybe try pulling that fuse (at least overnights).

 

[Colt Hero]

I would definitely try the Meter in-line and start pulling fuses ... even if you destroy them! You’ll probably get the hang of it by the 3rd or 4th fuse ... and only have to replace the 3 or 4.

Take a good picture before you start.

 

[Colt Hero]

@Trixie11 : One step at a time. Let’s see what you find with the inline Meter, pulling fuses one at a time.

Maybe you should buy some spares up-front so you’ll be able to immediately replace the damaged ones. You only want one fuse at a time pulled out.

You don’t think using the Channelocks or “Water Pump” Pliers will allow you to remove the Fuses without destroying them? I think you should be able to get the hang of it. You just need the teeth of the Pliers to grab very squarely at either end ... like in the video!

By comparison, the worst thing you could do is to use something like needle-nose Pliers because the teeth will be at a bad angle when you apply pressure. That’s how you can damage them. But with the “slip joint” Pliers you can grab it very squarely ... and then just apply the minimum pressure to be able the start slowly rocking the Fuse back and forth until it pops out ... just like in the video

 

[Colt Hero]

@Trixie11 : You've got the Meter set on AMPs/Current (DC) ... with a scale up to 20A, right? You're looking for a significant drop in Current when you pull each Fuse.

 

[Colt Hero]

@Trixie11 : Did you ever say you were seeing Battery-related messages in your Cluster? Things like "BATTERY SAVER ACTIVE" ... "LOW BATTERY" ... or "SERVICE BATTERY CHARGING SYSTEM"?

Was just looking through your Owner's Manual searching for what your vehicle considers a "Normal Parasitic Load" ... so you can report back with what you're seeing on your vehicle (and how far off it might be). It's not mentioned anywhere in the Owner's Manual, unfortunately!

There's also mention of the Electric Power Management (EPM) System (you had called it "EPS"??) ... where Voltage is constantly adjusted based on what the System thinks the current State of Charge is. This thing can actually increase Engine Idle to get more power out of the Alternator, or even turn OFF functions to save the Battery ("Battery Saver")! I didn't realize such a function existed! But I would think the only way it might damage your Battery is to inadvertently allow the Alternator to overcharge it ... (kind of like a bad Voltage Regulator) ... if it's even capable of that! Without my Shop Manuals handy, I don't know where it's located, or how to test it (or if this is a "Dealer-only" item ... it may very well be). Maybe someone else here can chime in with more information?

Also, in the Owner's Manual, there was a reference to the Ignition being left in the ACC/ACCESSORY or ON/RUN Position to kill the Battery. Now, I don't believe it's possible to leave the Ignition in either of these states with the Key removed, but maybe there's an internal issue with your Ignition Block that somehow makes this possible. This problem you're having is so weird that it wouldn't surprise me because it would be a "one-of-its-kind" failure. Maybe if you pull Mini-Fuse #32 ("Discrete Logic Ignition Switch") from the Passenger-Side Instrument Panel Fuse Block ... you might find a Current draw on that one ...