1996 LT4 draining battery
Thread Starter
Instructor
Joined: Feb 2009
Posts: 155
Likes: 1
From: Morgan city la
1996 LT4 draining battery
car seems to be draining battery When installing new battery connected the neg side first got some spark looked to make sure the positive wasn't touching undone the neg side and hooked it back got spark again finished installing started car all seems fine any suggestions would be helpful.
Thread Starter
Instructor
Joined: Feb 2009
Posts: 155
Likes: 1
From: Morgan city la
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
Disconnect the negative battery termninal and put a volt meter between, completing the battery circuit. Then, with the car off, see how many volts you are drawing... Then start pulling fuses of things that you feel might be shorted (radio, alarm, etc)... pull one fuse at a time and see if the voltage drops to 0... the fuse you pull to make the voltage 0 is where the potential short is... I tried this method on my truck and found my radio was shorted... I pulled the fuse, and bam, no more battery problems. A new radio later, the battery is back to normal!
Last edited by dogfish246; Nov 12, 2012 at 07:59 PM.
Burning Brakes
Joined: Nov 2010
Posts: 855
Likes: 36
From: Crystal Springs MS
car seems to be draining battery When installing new battery connected the neg side first got some spark looked to make sure the positive wasn't touching undone the neg side and hooked it back got spark again finished installing started car all seems fine any suggestions would be helpful.
That being said, Dogfish gave you some good troubleshooting advice.
Does the car have an aftermarket stereo, amps, or alarm system?
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Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
car seems to be draining battery When installing new battery connected the neg side first got some spark looked to make sure the positive wasn't touching undone the neg side and hooked it back got spark again finished installing started car all seems fine any suggestions would be helpful.
Have you checked with an external meter what you battery voltage is with the engine running?
Disconnect the negative battery termninal and put a volt meter between, completing the battery circuit. Then, with the car off, see how many volts you are drawing... Then start pulling fuses of things that you feel might be shorted (radio, alarm, etc)... pull one fuse at a time and see if the voltage drops to 0... the fuse you pull to make the voltage 0 is where the potential short is... I tried this method on my truck and found my radio was shorted... I pulled the fuse, and bam, no more battery problems. A new radio later, the battery is back to normal!
Reason being the car is not actually powered up. If there was a short directly off the battery you might find it. But lots of thing that need power are controlled by the CCM and if it is not power up, it can't turn things on.
The procedure is usually done using the current mode to measure current. Then you can see a large drop in current if you pull the fuse for a circuit with a short. Current should be less than 50 ma and usually is around 35ma or less with all off. If everything is off in the car with the battery connected and the current is in limits, there is no current drain.
Last edited by pcolt94; Nov 13, 2012 at 09:50 AM.
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
It's not uncommon to get a small spark when the last cable is connected. Current is drawn for the headlight control module, CCM, PCM power up, radio, hood lights and any interior lights that may be switched to ON every time the battery is connected.
Have you checked with an external meter what you battery voltage is with the engine running?
Although in theory, I have not seen this procedure performed in the voltage mode. Personally I would like to see it work properly on the corvette and prove me wrong.
Reason being the car is not actually powered up. If there was a short directly off the battery you might find it. But lots of thing that need power are controlled by the CCM and if it is not power up, it can't turn things on.
The procedure is usually done using the current mode to measure current. Then you can see a large drop in current if you pull the fuse for a circuit with a short. Current should be less than 50 ma and usually is around 35ma with all off. If everything is off in the car with the battery connected and the current is in limits, there is no current drain.
Have you checked with an external meter what you battery voltage is with the engine running?
Although in theory, I have not seen this procedure performed in the voltage mode. Personally I would like to see it work properly on the corvette and prove me wrong.
Reason being the car is not actually powered up. If there was a short directly off the battery you might find it. But lots of thing that need power are controlled by the CCM and if it is not power up, it can't turn things on.
The procedure is usually done using the current mode to measure current. Then you can see a large drop in current if you pull the fuse for a circuit with a short. Current should be less than 50 ma and usually is around 35ma with all off. If everything is off in the car with the battery connected and the current is in limits, there is no current drain.
Yea, I meant amps... That was a good catch! Thanks!
Burning Brakes
Joined: Dec 2008
Posts: 1,021
Likes: 7
From: Morgan Hill and Marina California
What pcolt said, with one more comment: make sure you know where
ALL the fuses are. Check the easy ones in the big fuse box first, but
there are likely a few somewhere else.
And you might want to start by pulling the fusible links. On my '87, FSM
shows 11 (A through M, I didn't see I and L, so 11, and there
may be two more). Only one leads to the fuse block.
Cuck
ALL the fuses are. Check the easy ones in the big fuse box first, but
there are likely a few somewhere else.
And you might want to start by pulling the fusible links. On my '87, FSM
shows 11 (A through M, I didn't see I and L, so 11, and there
may be two more). Only one leads to the fuse block.
Cuck
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Your right , "most people might have known what he meant". But these threads are read by thousands of people of all ages some with limited electrical troubleshooting experience and knowledge.
Let's not make it any more difficult for the ones trying to learn by putting out information that is 50% correct or such. That might send them off in a tangent somewhere in conflict to what they are trying to learn or have learned.
Let's be 100% correct as much as possible.
I knew what he probably wanted say but did not want to "bash" dogfish for a honest mistake. Just wanted to set the record straight as best I could and correct the error.
Let's not make it any more difficult for the ones trying to learn by putting out information that is 50% correct or such. That might send them off in a tangent somewhere in conflict to what they are trying to learn or have learned.
Let's be 100% correct as much as possible.
I knew what he probably wanted say but did not want to "bash" dogfish for a honest mistake. Just wanted to set the record straight as best I could and correct the error.
Melting Slicks
Joined: Jul 2005
Posts: 2,649
Likes: 863
Measuring curent draw when the car is off is the RIGHT way to do the job, but there are some times when the current draw is higher than it should be, and none of the fuses seem to make a difference in the current draw. If that's the case - try disconnecting the alternator wiring (bad alternator diode), and/or the PCM / CCM wiring.
Racer
Joined: Mar 2012
Posts: 456
Likes: 4
From: Columbus Oh
My '91 drained a brand new battery while parked in my garage for 8 days. I'm seeing .2 amps of current draw with nothing turned on. If I pull the radio fuse it drops to .18 amps. I pulled all the fuses in the fuse panel and had no change in current draw. Currently I'm doing an engine swap and when I get to where I can test from the fusible links on the starter, I'll isolate which circuit has the draw and start through the service manual to see what's on that circuit. Hopefully that will allow me to track it down.
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
Suggest starting off with anything which is not working or working correctly.
Most likely culprit will be a relay which is stuck.
A few things to check:
1. DAB (delayed accessory buss) -- turn on key, on radio, off key, remove key, radio should remain on, open door, radio should turn off. If it does not turn off, then the DAB may be remaining active which would drain the battery. Classic reason: door ajar switches sticking or failed electrically.
2. Antenna -- occasionally the built-in relay gets stuck and continues to draw current albeit it might not be loud enough to hear it continuing to run.
3. Seat motors - seat covers might pull the switch keeping it running, or the console switch is being depressed or failing and feeding power continously.
4. Interior lights -- albeit during daylight might not be lit, once darkness sets, the 'light sensor' may enable them -- if -- they are not turning off correctly (e.g. again door switches or alarm system or door locking system not working correctly can cause this).
5. Leaving keys in ignition or not locking the car doors. Both cause the CCM and PKE systems to remain active which substantially increase current usage.
Finally, review your FSM, it does indicate the 'stand by' amperage draw your year/model should normally draw.
Most likely culprit will be a relay which is stuck.
A few things to check:
1. DAB (delayed accessory buss) -- turn on key, on radio, off key, remove key, radio should remain on, open door, radio should turn off. If it does not turn off, then the DAB may be remaining active which would drain the battery. Classic reason: door ajar switches sticking or failed electrically.
2. Antenna -- occasionally the built-in relay gets stuck and continues to draw current albeit it might not be loud enough to hear it continuing to run.
3. Seat motors - seat covers might pull the switch keeping it running, or the console switch is being depressed or failing and feeding power continously.
4. Interior lights -- albeit during daylight might not be lit, once darkness sets, the 'light sensor' may enable them -- if -- they are not turning off correctly (e.g. again door switches or alarm system or door locking system not working correctly can cause this).
5. Leaving keys in ignition or not locking the car doors. Both cause the CCM and PKE systems to remain active which substantially increase current usage.
Finally, review your FSM, it does indicate the 'stand by' amperage draw your year/model should normally draw.