2007 Tahoe Sporadic Parasitic Battery Drain

[Dlewis59]

Help! I am at wits end on this issue. I have very well maintained 2007 Tahoe that started having a dead battery issue. I originally thought it was just the battery, but after several replacements have discovered it’s a parasitic draw. It happens sporadically however, not every night. The last interval was 30 days between dead batteries. In the past it has gone multiple months between dead batteries.

I have had multiple mechanics in on this as well as my local dealer where I purchased it new. They all have run an Amp draw monitor, as I have too, the last being my local dealer who monitored it for 3 days on an amp meter. The electric system appears to function normally, going to sleep and pulling about 14mA while sleeping. Nothing woke up.

I needed the Tahoe for the weekend, so I picked it up from the dealer after they monitored it for 3 days and finding nothing. That was a Friday. On Saturday we drove it about 75 -100 miles, then parked it in the garage. On Sunday I backed it out of the garage to empty the equipment and pulled it back into the garage. It sat the rest of the day Sunday and Sunday night. On Monday morning, it was dead again. The battery voltage read 7.3V.

I don’t want to just start spending $ to replace components that are the usual suspects (Nav Display and system, Bose Radio/Amp, instrument display, a/c controller, etc.).

Any thoughts or experiences or help is much appreciated!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

Parasitic draws are a nightmare, as you have found out, particularly when it is intermittent.

If I were in your shoes, I'd probably do something like installing a second battery, and link it to the main fuse with wires that have high amperage quick disconnects. The disconnects are normally disconnected (except for occasional connections to keep the battery charged). Then, if you have an issue, you connect the second battery to get the truck started, and you can be on your way. I have this setup installed in my truck, just in case that I have a battery issue sometime in the future, when I'm out on the road somewhere.

I cannot personally assist you in the specific troubleshooting of your parasitic draw issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

 

[mikez71]

No idea if the alternator diode could be intermittent or not.. maybe worth testing..

 

[solli5pack]

Only way you're going to find the draw will be to troubleshoot when its happening. Hook up an amp meter between the battery negative post and the clamp and when the draw is happening start pulling fuses until it goes away...

 

[Fless]

Think about using a thermal camera to see if any relays are sticking or if anything is getting warm from being awake.

 

[West 1]

So your issue comes and goes, hard to find for sure. My 2007 Escalade had a draw that drove me nuts. Finally found it was the under hood fusebox itself, the draw was in the lower box where hundreds of wires come in and out. New box and trouble gone but you have to isolate where the problem is or you are wasting money. South Main Auto on YouTube has some very good videos showing chasing battery draw issues and shows a variety of ways to look for the problems.

 

[OR VietVet]

Welcome to the forum from Oregon.

Like @Fless said, a thermal imager can help but would need to be failing when you are checking.

What @solli5pack said is the tried and true way to check with but there is better technology out there and check out https://powerprobe.com/wp-content/u...2_PP_PPDRAW_Manual_100x200mm_V4.pdf-1.pdf.pdf

You do not unhook the battery to use this tool. It attaches at the DLC.

Since your problem is so very very intermittent, I think I would try removing fuses or relays, one at a time and only reinstall if the circuit is needed when driving. This will take some time, unless your first removal choice is the culprit. If you do just that one fuse/relay for let's say a month, and you have no problems, then that circuit is the likely culprit.

The "battery several replacements" is concerning too.

 

[West 1]

Keep in mind when pulling fuses that simple act can wake up systems and it may be 10-20 minutes before they shut down so you can continue searching. Do some study before starting your testing.

 

[homesick]

Keep in mind when pulling fuses that simple act can wake up systems and it may be 10-20 minutes before they shut down so you can continue searching. Do some study before starting your testing.

Is it possible that pulling and reinserting fuses could improve a connection enough to solve the problem?

joe

 

[OR VietVet]

Keep in mind when pulling fuses that simple act can wake up systems and it may be 10-20 minutes before they shut down so you can continue searching. Do some study before starting your testing.

Pulling a fuse will not wake up a system. Installing a fuse can do that. When you have all fuses installed and relays, then the different systems can take several minutes to shut down, "go to sleep".

 

[West 1]

I guess if you choose to pull fuses and leave them out as you test you should take pictures so they go back to the proper location, the fuse box door does have a diagram to help with this also.

 

[Fless]

I guess if you choose to pull fuses and leave them out as you test you should take pictures so they go back to the proper location, the fuse box door does have a diagram to help with this also.

And once you identify the offending circuit, you'll likely need to look at an electrical diagram to see what's powered by it. You can find diagrams on www.charm.li.

 

[Fless]

Is it possible that pulling and reinserting fuses could improve a connection enough to solve the problem?

joe

Yes, but that's rare. And it's also the reason that pulling fuses isn't necessarily the wisest way to track down a draw, since exercising the fuse contacts may not point to the cause.

Of course, checking fuse pin tension in the fusebox sockets might be helpful.

 

[homesick]

Yes, but that's rare. And it's also the reason that pulling fuses isn't necessarily the wisest way to track down a draw, since exercising the fuse contacts may not point to the cause.

Of course, checking fuse pin tension in the fusebox sockets might be helpful.

LOL, 'almost never' is my specialty. I'm a magnet for unusual problems.

joe

 

[Dlewis59]

Thank you to everyone for the insights and suggestions! I’m very happy to connect with all of you on this forum.

Even though the first thing I tried was to replace the alternator when I was having the batteries die, I will see about doing an alternator diode test as suggested by @mikez71. Thank you.

Also, I do like what @OR VietVet suggested about pulling fuses over time to see if it continues to do it. This was actually suggested by a close friend of mine who was the service manager for years at several GM dealerships in San Diego. I bought a tool on Amazon that he suggested to make this easier. https://a.co/d/hZTdaUz A fuse switch that you can just turn off when parked overnight, and turn back on when you’re going to drive. I may revert back to this. Also, I just bought one of those new monitors you posted. Going to try it and record the monitor overnight to see if anything is waking up at night (obviously something is!). That unit can connect via Bluetooth to a phone. Plug them both into power so they stay up and it will record the nights activities according to the company that makes it.

All of these are great suggestions guys. Again, my thanks!

I’ll let you know how it goes. If I can find it, maybe the procedure will help others…

Also, @Joseph Garcia asked for some photos of my “Hoe” as I lovingly call her. This is my baby….

 

[Fless]

Don't use the "pull the fuses" method, since it can wake up modules during the test; there's an easier way. There are lots of good YouTube videos on diagnosing parasitic draw. Here's one:

 

[Dlewis59]

I have another theory on this issue that I’d love your opinion on. I noticed that yesterday when I connect my battery analyzer/charger to the battery, it showed 40% capacity. I thought that was strange as I had it was disconnected while doing the overnight monitor test with the power probe tool, had been driven during the day (thus charging), and was completely recharged to 100% capacity just a few weeks earlier.

Here’s the thought, I put a new alternator in a year ago, and replaced the negative battery cable per the GM service bulletin. I’m wondering if the positive cable also should be replaced? If there’s too much resistance in the cable, the amount of current flowing to the battery would be reduced and even though the system shows generating 14.1V most times (it does drop occasionally to 12V-ish at times) that doesn’t mean that the battery is getting the current. This could mean that I don’t have a parasitic draw at all, but rather the battery is just slowly being starved of current until it gets to a point where it can’t hold up over a night or two of normal mA draw.

What are your experiences with this scenario? Unlikely? Thoughts/suggestions?

 

[Fless]

Do a voltage drop test. The battery cables tend to rot from the inside; although an ohm test might/would show continuity, nothing tests the capacity of the wire to pass current like a voltage drop test.

 

[mikez71]

Could be your battery is already weakened from being run down too far/many times..
I get it, you don't want to put a new battery in while something is killing them!
But at this point with the battery down to 7.3V more than once, it might be hard to test with that battery..

If get a new battery, I would disconnect it everytime on shutdown until I found something that could be the culprit..
Meantime check the voltage when you shutdown.. should show if undercharging before too long.

There was a thread on here were someone had to buy 3 alternators before getting a good one. Even a dealer OEM was bad!
His issue was flickering lights..

 

[homesick]

I have another theory on this issue that I’d love your opinion on. I noticed that yesterday when I connect my battery analyzer/charger to the battery, it showed 40% capacity. I thought that was strange as I had it was disconnected while doing the overnight monitor test with the power probe tool, had been driven during the day (thus charging), and was completely recharged to 100% capacity just a few weeks earlier.

Here’s the thought, I put a new alternator in a year ago, and replaced the negative battery cable per the GM service bulletin. I’m wondering if the positive cable also should be replaced? If there’s too much resistance in the cable, the amount of current flowing to the battery would be reduced and even though the system shows generating 14.1V most times (it does drop occasionally to 12V-ish at times) that doesn’t mean that the battery is getting the current. This could mean that I don’t have a parasitic draw at all, but rather the battery is just slowly being starved of current until it gets to a point where it can’t hold up over a night or two of normal mA draw.

What are your experiences with this scenario? Unlikely? Thoughts/suggestions?

My question about reseating fuses fits with this. All electrical connection points, maybe especially ground connections, should be checked.

joe