And another electrical problem - battery drain

[Jeff]

In addition to my starting problem, http://www.turbobuick.com/forums/showthread.php?s=&threadid=45579
I also have a battery drain that seems to be pretty bad. Today I hooked a voltmeter between the positive terminal on the battery and the positive cable with the key off to see what was draining the battery. The first thing I noticed is that the drain doesn't appear to be constant. The voltage would be at 12.75 volts, then drop to about 12.5 or 12.3, then go back up. I pulled every fuse, and there was no change. I even pulled the two battery leads off the fuse box with no change. All this with the door open...so when I closed the door the voltage starts dropping and gets down to 12.2 volts. I am thinking that the factory security system is messed up and causing this problem. Is there a way to disconnect power to the security system and see if the drain goes away? Could this also be the source of my starting problem?
An explanation of how the security system is supposed to work would be helpful to me, also. This is a theft recovery car so chances are the system has been tampered with.
Thanks in advance,
Jeff

 

[2QUIK6]

Well first off, if you are measuring voltage, it will always be around 12v if there is an electrical current present, you need to measure the current/amperage draw. To measure how big of a drain you have, disconnect the negative side battery cable. Set up your multi-meter for mA current, and put a multimeter terminal on the negative side cable, and the other multimeter terminal on the negative side of the battery post.
Make sure everything is off and doors closed and light removed from hood, you may see around .02 or so from the stereo clock and memory and that should be it.
If the security system is "armed" it will draw some as well.
Its best to disconnect the security alarm, especially being that you don't know anything about it or its history. You will usually find a wire coming from the "brain" of a alarm module that goes somewhere on the fuse box, just remove that wire or in-line fuse and you should be set.
Yes, many alarms have a "kill switch" that prevents juice from going to the starter/ignition, if this is faulty, then it could prevent the car from cranking over to start, yet everything else will work fine.
If you can't figure it out, it probably best to take it to any place that installs alarms and they should be able to disarm and decommission it for you for very cheap $$.

 

[Jeff]

If it was an aftermarket system it wouldn't be a big deal, those are usually easy to spot and remove. What I am talking about is the factory system. There's a "security" light on the dash, same asmy dad's '86 Corvette. I'm not sure exactly how it's supposed to work, or if it even has a starter kill. Another possibilty would be the neutral safety switch, I suppose...
Jeff

 

[2QUIK6]

You'll have to ask a dealer about the alarm, or maybe someone on here knows how the factory one works. I'm thinking only the radio is protected, seems like the old radios used to not work after having the power cut off or something unless you entered a "code" of some sort into it by pressing certain buttoms in sequence.

 

[Maltman]

double check power master circuit.....mine is drawing about .2 amps....and i'm losing about .46 amps overall!! Stinking radio/crtsy circuit (mainly the radio).

Good luck, I've given up and decided to live with it for now

Mark

 

[Jeff]

Thanks for the many replies!

While chasing my starting problem I found that someone has cut and spliced several wires in the starting harness, which I assume are related to the factory alarm and were tampered with when the car was stolen. I've got the starting problem figured out (sort of, at least it will start now) so maybe the battery drain isn't as bad as I thought. I'm leaving the battery disconnected while I travel this week and will play with it again when I get back...

Anyone with info on the factory alarm system or where to get a good electrical schematic please let me know.

Thanks again,
Jeff

 

[2QUIK6]

Originally posted by Maltman
double check power master circuit.....mine is drawing about .2 amps....and i'm losing about .46 amps overall!! Stinking radio/crtsy circuit (mainly the radio).

Good luck, I've given up and decided to live with it for now

Mark

Hey Mark, I had exactly the same amount of draw from mine, turned out to be the coolant fan delay relay as its wired into the same circuit fuse as the power master. The realy is the largest relay on the drivers side fender closest the firewall, you'll notice the wires from the harness go there and to the power master switch/harness. Unplug the wires going to the relay and see if your battery draw current goes away The coolant fan delay is only there to keep the fan running after you shut the engine off, it should run a few seconds until the coolant temp is down to some predetermined value, can't remember the exact # as mine has never worked in 12 years, but just discovered the drain a few weeks ago.