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How To Test 2005 Chevrolet Tahoe Dead Battery Draw

I have a Chevy Tahoe 2005 4×2 and something keeps pulling battery down. I was told to hook a test light to negative side of and did it and pull all fuses one at a time and light stays on. Need help.

ProTech:
You were told the completely wrong way to check for a draw on the battery. Using a test light is a very poor way to check for that. A test light will light at different levels depending on what is drawing power. I have been doing this for 20 years and still can’t tell from the brightness or dimness of a test light how much current is drawing from the battery. You need a meter to do it correctly. Some modules stay on for quite a long time, others for a short period. They all draw different amounts of current. Do you have a meter that measures amps?

Yes.

How To Repair

ok…follow these instructions exactly. Disconnect the negative battery cable, and attach one end of the meter to the cable and the other lead to the battery. The electronics on the truck will power up for a second and you will see a large draw to start with. Allow at least 10 minutes for all modules and electronic accessories to power down. After that, you should hopefully have a draw of less then 80 milliamps. That would be 0.080a on your meter. Anything over that and you have a draw that will kill the battery and will need to find what it is.

Yeah they told me to unhook negative side and put one in of test light to battery and on in on cable and if light is on its pulling power then pull fuses one at a time until light goes off , I have been just unhooking negative side every time i stop some where but ac started acting up to it will blow soft then blow hard when it wants to.

Do NOT use a test light, that will not work at all! You will not get accurate readings.

Ok how would i find where the problem is?

Well first you need to see if you actually do have a problem!

If i unhook battery negative side when i stop it and hook it back up when I leave it will crank if I don’t unhook it it will be dead and have to get a jump and A/C started blowing when it wants to it will blow soft then blow hard.

Are you leaving the blower on automatic? It will start like that if you are. Other wise you may have a bad control head that is causing your draw, if you have one.

No blower can be off and it will do it , where is a control head see hear is where it started the ac blow would atay on at first so i figured that out and and was just pulling fuse until I could get it to mechanic then even after you pulled fuse it was going dead so now that’s where I’m at even with blower fuse out it goes dead.

The control head is where you turn on and off the heat/air conditioning. If you are still going dead with that fuse out, then that’s not the problem. It may be a problem, but it’s not causing your battery issue.

A/C blower is one problem cause when car is off and key is out the blower still blows unless you pull fuse and hold it out for second then you can put it back in and blower stays off until you crank it again ,,how would i located the problem?

If you are showing a draw after you’ve done what I told you to do to check for it, you would need to start pulling fuses from all three fuse blocks on the truck. Once the draw disappears after pulling whatever fuse, you know your problem is on that circuit and can go ahead and start tracing the wiring and looking for the short.

Oh, ok i see now thanks a whole lot.

One more question what should the meter show if there is no draw 0.080a ?

With an acceptable draw, it should be anywhere from 0.080 or less….anything over is bad.

Thanks. I wish you lived close to me i would just bring it to you.


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