How to find an electrical drain

[Bloodhound]

I have a problem with my truck. The batteries keep draining. How do I track down the drain? I will start by disconnecting all of the aftermarket electrical components. But what do I use to look for a drain.

 

[surewhynot]

I don't know if it will work on a newer computer controlled vehicle because of the electronics that may have a constant draw, but here's how I troubleshoot.

Disconnect the negative cable from the battery (s). Hook a test light to the unhooked negative cable and ground it. If there is a draw, the light will light up. Unplug fuses until the light goes off. Then you know what circuit is causing the draw.

 

[Bloodhound]

thanks for the info. I didn't know about the test light.

 

[blacksnapon]

Start with your radio. Strangely, I've had a bunch of them be the cause of it.

 

[LEB Ben]

Nothing to really add...but I too would recommend Tony's method. I can't stress enough how important getting a good ground is...and make sure the test light works first...nothing pisses you off worse than testing all the fuses and you figure out your bulb is broken/burned out...ask me how I know.

 

[Truckin4life]

I always test before i use a test light ben...
Its become habit cause ive done what you have mentioned one time to many...



Have you had any aftermarket electronics installed recently?
What kind of driving do you do?
Rough dirt roads by chance?

 

[blacksnapon]

What helps is a piece called a parasitic draw test adapter. Several times, a draw will be there, then when you disconnect the battery, and reconnect (installing the test light) the draw resets, and its not there. Install the draw adapter, then test drive, using all the bells and whistles. The adapter will allow you to install a tool (test light, ammeter) without completely disconnecting the circuit.

 

[Mil1ion]

http://www.inliners.org/tech/tech6.html

 

[surewhynot]

I never knew they made such a thing Vince. That's good to know.

 

[Bloodhound]

Thanks for all of the info. I hope to be able to work on it sunday. If we get the new work van lined out. See my post in the e series section for details.