Need help with battery shut-off switch

[Reverend B]

2003 Chevy Silverado, 205,000+ miles. Something is drawing the battery down. Long story but I've replaced the battery 3 times within a year and a half. I took it to a local shop who could not figure out what was drawing the battery down. So, today, I installed a battery cut-off switch. I turn the switch to "on" and truck starts right up like normal. With the switch in the "off" position, I put the key in the ignition. It won't start but the dash lights up and it dings when I put the key in the ignition. Isn't the switch designed to prevent ALL current flowing from the battery? Does this mean that its possible that whatever was drawing the battery down still cause a problem? Any ideas??

[jbsoonerfan]

This might sound crazy, but I had a buddy who's wife's 08 Tahoe was acting similar. He took it to 2 different shops after replacing the battery and the alternator. Turns out it was a bad ground that runs from the battery to the alternator. No idea why your dash lights would work though with a cutoff. I am NOT a mechanic, just passing some info along.

[bassboat1]

Curing the problem is better than a workaround IMO. If it's intermittent, it will be a challenge to find but otherwise it's pretty straightforward. SMH vid:

I was doing some work on my '03 Silverado yesterday and found this sucker, rubbed through on a bracket. That's a 6 or 8 ga wire...

zzz.jpg

[rboren]

The computer system has ability to stay live for several days. It will not start the engine but body controls may stay active. Depending on where you put the switch it eliminates most functions. I have a LOT of experience with vehicles. A simple way to start finding problem is to take a test light and connecting clip end to battery and the sharp point to end of cable you disconnected. A dim lit test light can be normal but a bright one is not. Start removing one fuse at a time and check test light. When it goes out or gets dim you have found the circuit that has the drain. Research what is in the circuit and check each one at a time for a problem. A current draw meter is best but isn’t needed. I worked as an instructor for a college and for GM and Ford also. Nothing DEA different from one brand to another. Just more stuff in circuits on some. By the way I have a 2093 Tahoe we bought new. It has been the best vehicle we have ever owned.

[JR19]

A battery cut off switch will kill power to everything but only if installed in the correct place. It needs to be near the + positive battery post and ALL devices going to the +positive side of the battery must go through the disconnect to kill power to everything...now with that being said that is a band aide fix which does not correct the real problem but it will kill everything going to the battery.

[Transom]

Follow the current.

[CJ1]

I am betting you just put the switch in the starter line and the rest of the battery is still hooked up to the truck. look for extra wires in the battery connection. CJ

[mwill29]

You've got a parasitic draw somewhere. Too bad you are in Jasper...I've got a shop in Ky. and I love diagnosing and repairing parasitic draws. I agree with others that the switch isn't killing all the current. I recommend finding and repairing the draw. And with computer control vehicles you can't "watch the current meter and pull fuses" anymore, if you wake a module in the process than your current will be all over the place. The test light in series at the battery isn't a useful test anymore either, you need a current meter.

[djb750]

Could be a myriad of possibilities, BUT given the age of the vehicle I would check and clean ALL GROUNDS. The first is the negative batt to frame. Check some Chevy blogs for potential fixes as a lot of times there's a known culprit.

A guy in the office used to own a Saab with the GMC engine. GMC apparently went hog-wild with the engine grounds on this model (seems like there were 15 grounds or something stupid like that). He went thru a 2-year phase where it would randomly die when the turn signal was operated, along with other electrical gremlins that were all due to corroded negative grounds. It was an entertaining 2 years for us watching him go thru it, because he's notoriously bull headed, and did nothing more than a visual check on some of the grounds.

Without proper grounding, DC voltage will do weird stuff, and chasing down electrical gremlins can be super difficult. Start with the basics.

[CRAWFW]

Just wondering if you put the switch on the neg or positive wire?
I had one installed on a little hot rod I bought and still had current draw.
I ended up putting it on the positive side and it fixed the amp draw.
Not a cure but a workaround no doubt.