It's been cold & rainy here so I haven't gotten as much done outside as I would like.

The Tahoe was starting for more than a week as long as I used it each day. Two days ago, I drove it during the day, parked it at 4 pm, and the battery was dead at 9 pm. I swapped in the spare, fully charged battery and drove the truck, parked it after midnight--dead the next morning.

Today we put the ammeter in series with a charged battery. The truck was drawing 9.8 Amps. Checked a few connections, got a small spark grounding the meter to the alternator housing, and the draw dropped to 3.5 Amps.

Removed all electrical connections to the alternator... no change.

Removed the LBEC 1 (50 Amp) fuse -- drain dropped from 3.5A to 1.5A. Left that one out.

In the underhood fuse block, pulled all relays and all of the large fuses... no change.

I realize this was not the 5 hour test, but hopefully there is some useful info here.

 

Thanks for the replies. Had to work around all the rain we've been having.

The time to sleep mode turned out to be less than 10 minutes once I found the real problem.

I read through this thread and sort of combined it with all the advice. I got a battery disconnect switch (for my side-mount cable) and added a couple of small screws to clip my multimeter leads to. This made it really easy to leave the battery in the circuit and check the drain whenever I wanted to, by turning on the multimeter in the correct Amps mode and then using the switch to disconnect the negative cable from the battery (the meter leads bridge the disconnect switch).

I again found about 9.8 Amps flowing. That is so large...

But I had found free wiring diagrams here, and I was able to see which I/P fuses (on the drivers side inside panel) were coming from which underhood fuses--that helped a lot. One of the downstream fuses was for the driver electric seat controls. And guess what--over the years the screws holding the trim on the left side of the driver seat had loosened (most had fallen out), and sometimes the trim would shift enough so that when the door was closed, the hard plastic "pocket" molded into the bottom of the door would engage the switch in the "front down" position--that was my 9+ Amps draw. At some point, this would apparently "cut out", but it seemed to keep other systems awake for a long time.

I found the part number for the black screws for the trim--GM sets a price of $10.10 per screw. Typical. I found better screws at a hardware store for 33 cents each. Got the trim back in place and the 9+ Amp drain is gone. At first, the drain is 3.6 Amps, then the dome lights fade out and the drain drops to 1.5 Amps. Within 10 minutes, the systems go to sleep and the drain is a steady .0156 Amp, i.e. 15.6 milliAmps (mA), well under the 35 to 50 mA "normal" threshold (no OnStar, thank you very much). The truck has been starting faithfully for almost a week now.

So it was my stupidity to not replace the driver seat trim screws as each one fell out. Dumb.

Thanks for the replies.

 

Nicely done detective. Great follow through.

 

I have a 2007 Tahoe (post below). Do you think my issue could be the driver’s side power seat switch as well?

I’ve taken great care of this car since 2011 (every service, only has 119,000). Unfortunately, we’ve had 9 years of dead batteries and odd, intermittent electrical issues.

What we’ve done:
- new batteries every 18-24 months
- new alternator and starter
- new BCM installed at dealer

What has/still happens:
- stock stereo/nav/computer runs/stays on for 15-20 minutes after ignition off AND you can hear it begin booting-up any time you open door.
- power driver’s seat
works briefly 2-3 times a month AND only one time.
- rear hatch door works most of the time, but not all of the time.
- drivers side power mirror stays extended, but you hear the motor run for the full length of time after pushing button.
- car battery will die if DVD player (stock) is on for a any length of time while car is off.

I’m really a novice and don’t have a lot of money to throw at this.

I’m planning to sell the car next week and want to solve the electrical problem for the next owner. It’s a really nice 07 with super low miles.

Thanks!!!

 

Yes, very good.

 

[QUOTE=scrnchr;276952]Thanks for the replies. Had to work around all the rain we've been having.

The time to sleep mode turned out to be less than 10 minutes once I found the real problem.

I read through this thread and sort of combined it with all the advice. I got a battery disconnect switch (for my side-mount cable) and added a couple of small screws to clip my multimeter leads to. This made it really easy to leave the battery in the circuit and check the drain whenever I wanted to, by turning on the multimeter in the correct Amps mode and then using the switch to disconnect the negative cable from the battery (the meter leads bridge the disconnect switch).

I again found about 9.8 Amps flowing. That is so large...

But I had found free wiring diagrams here, and I was able to see which I/P fuses (on the drivers side inside panel) were coming from which underhood fuses--that helped a lot. One of the downstream fuses was for the driver electric seat controls. And guess what--over the years the screws holding the trim on the left side of the driver seat had loosened (most had fallen out), and sometimes the trim would shift enough so that when the door was closed, the hard plastic "pocket" molded into the bottom of the door would engage the switch in the "front down" position--that was my 9+ Amps draw. At some point, this would apparently "cut out", but it seemed to keep other systems awake for a long time.

I found the part number for the black screws for the trim--GM sets a price of $10.10 per screw. Typical. I found better screws at a hardware store for 33 cents each. Got the trim back in place and the 9+ Amp drain is gone. At first, the drain is 3.6 Amps, then the dome lights fade out and the drain drops to 1.5 Amps. Within 10 minutes, the systems go to sleep and the drain is a steady .0156 Amp, i.e. 15.6 milliAmps (mA), well under the 35 to 50 mA "normal" threshold (no OnStar, thank you very much). The truck has been starting faithfully for almost a week now.

So it was my stupidity to not replace the driver seat trim screws as each one fell out. Dumb.

Thanks for the replies.

 

Wow !!!

 

what is drivers seat trim screws

 

that person is long gone. Are you having an issue with your car?

 

I had the same problem battery would go to nothing but was new. It would work ok if I started each day but would drain if not started. Problem was an intermiattant short in alternator. Replaced have gone down in 6 months with as lomg as 10 days without starting