ts18997

I have a 1999 Suburban K1500 that keeps killing batteries. First, old battery died. Replaced and truck sat for couple weeks. New batter went dead. Thought it was a fluke. Replaced with 2nd new battery. It too died after couple weeks truck sitting unused. Now, I dont connect the battery until I need it. What could be causing this? I dont see any lights or other devices left on during the lull time. How can I diagnose this issue? Will a meter hooked up to the battery while I pull fuses one by one show anything like a load being pulled?
Thanks.

ts18997

BTW, I saw some posts on using a meter. When I hook it up between the negative cable and the battery, it shows to be 12mA. That sounds like a normal drain due to the features that have memory on the vehicle. Could that still indicate a problem. I ran the test at the fuse box and found 5 circuits that have the same 12mA reading.

ts18997

Forgive the previous post. I'm a noob with a multimeter. The numbers I posted were obviously the voltage I was misreading. Now that I have a better understanding of the multimeter, I find that I am blowing the .5a fuse in the multimeter when I try to read the the current reading between the battery and the negative cable (the key is not in the vehicle when I do this). Does this seem to indicate a large short? Should I start with the alternator or something else to rule out causes? Lastly, how can I debug this if I cant even use the mutimeter to see what circuit has the issue? Am I back to using the old light bulb on the circuit trick? Any other suggestions?
Thanks, Mark.

RonH

Here's an article that may be helpful to you:

http://www.aa1car.com/library/battery_runs_down.htm


Good luck

ts18997

Thanks Ron, that is similar to other excellent articles on shooting this type of problem. What I have read on several posts was to set the multimeter to amps(current, not volts) and then test between the disconnected negative cable and the negative battery post. If there is a short, it should show as current being pulled off the battery (something more than 15mA or so). That is also why a light bulb would light if put on the same circuit. Again, not an expert here, just following other posts. As far as voltage, the new battery is staying at 12.7 volts because I have not left it hooked up (dont want to kill a 3rd new battery). Since the meter keeps blowing fuses (meaning I think that the short is drawing more than .5a) I went back to the light bulb trick. Whats confusing me is that the light bulb lights initially, it wont stay lit. This is confusing the #*&*&$ out of me. Seems like there is an initial draw when the light bulb is put on the circuit and then drops off. Maybe this is an initial computer current draw similar to when a new battery is connected. I'm just guessing at this point. If I had some consistent method (multimeter, light bulb) to see when pulling a fuse makes a difference, I could start to shoot this bug. Without some sort of indicator, I'm going to be pulling one fuse every night, checking the battery the next morning, and risking killing yet a 3rd battery. There has to be a better way, I just dont know it. Thanks for the assistance so far, electrical work is frustrating.

ts18997

Well, I think I have resolved the problem. I had a previously broken passenger side vanity mirror light that was disabled when the flip cover broke. The drivers side was always fine...until I checked it. One side of the hinge flip cover was broken, the side that also has the push on/off button. Dont think it was getting enough pressure to turn off and because its tucked up and away, never saw it. Battery has been hooked up and looks like charge is holding. Still dont know why I had so much trouble using a multimeter to measure the amps draw nor the test light bulb trick but I'm putting this issue to bed for now. THanks for the help.