1 Amp Draw, Drains battery, help!!
 

I bought this 2002 Monte Carlo SS about 2 weeks ago, and for the most part I drove it a lot, never sat more than 24 hours at most. I walk out to start it after it sat about 24~25 hours at the battery was at 5 volts. I charged it up and went on my way, figuring I the door slightly open or something. I come back 12 hours later, starts fine, but all I do is start it and shut if off, then walk away. I walk out to it again about 11 hours after that (23~24 hours since I charged it up after finding it at 5 volts) and it was way down again, no start. Battery was replaced 10,000 miles ago, in Feb of 2016. I looked for a short this morning and found that the battery has a draw of 1 amp that starts very randomly, but always last 15~16 seconds. It is very steady of 1 amp for 15~16 seconds. The draw then stops for anywhere between 12~120 seconds, and then the draw comes back for another 15~16 seconds. I would assume this would involve the radio or BCM, for it seems to have a mind of its own to be so regular. There is also an aftermarket security and remote start in the car, all disconnected. It is Python security of some sort. If anyone can help me pinpoint the draw, i'd appreciate it greatly.

Thanks

This is a pure guess, based on past experience. My first car. a 1981 Plymouth TC3, had exactly the same kind of light switch you have. It was shorting out and killing my battery. I had neither money or mechanical skills at the time, so I just turned the dimmer all the way down during the day, and it stopped the draw.

First I hate to say it can be hard to start with to find a Draw on these cars. One reason is for the first 20 to 30 minutes there can be a Draw as you stated for the computers to do checks and things like that. At times it can seem like it is gone and then comes back. There is 1 Big problem with doing a Draw test. One you have to put a Meter in place. So when you take the Battery cable off it will reset the computer to turn on to make these checks. Then there is the ability to not have a good connection and in turn it will make it so again the computer starts doing the warm up the cool down type of things.

So really the best way to do testing for Draw on your car is to pop the hood, Take any Alarm hood pin you have connected or even a hood light pin and disconnect it, Open fuse boxes. Also you can trick your car into thinking your cars door is closed this needs to be down to where it thinks it is closed and not just ajar. Also if you know for sure there is no draw in your Interior light system. remove that fuse as well. YOu need doors open to do the testing on the inside boxes.

Once you have your car setup for all doors to be closed Press the lock button on the drivers door, Then flip the latch so the door shows closed. you will see the light dim to off. Then wait 20+ minutes

Test the 60amp fuse in the underhood box with your meter set to Volts 2 if it is An Auto Ranging meter that is better. Test over the Fuse from pin to pin. Then next one your looking for a Voltage Drop over the fuse. This drop if more then 0.005 needs to be looked over for where it may be shorting. Once you look over all the fuses in the underhood boxes then move into the inside boxes and again test them over the fuses. The smaller the fuse is the harder it is for the DVOM/DMM probe tips to get into there. So if you have some good SMD testing tips that would be best for these tests. I am sorry I might be low in my testing numbers too. So it could be 0.05. however when you test your car you will see the drop that is over your fuse and you will see what is high or low. Right now I can't test either of my cars to give a good number because my children thought it was nice to use my cars for their weekend trips. Son has my MC and daughter has the Impala. Left me with my boots lol.

Please note you can test over the Fuse for a Voltage drop if there is voltage over the fuse there is something in that circuit that is using power.

The Rap System turns off after 10 min, The BCM stops most checks after the first 20 minutes and cold be as long as 30 minutes. There will always be a draw in the car because the cars computer is looking over the Security system to make sure that your not pressing the unlock, lock or trunk button. Also Radio memory as well.

Most newer then 2013 cars even have a larger draw then older cars because they have more computers that stay awake over the time your away.

James

I have made further discoveries, I do believe my radio is locking from time to time due to this issue. I also have gotten other random messages come up on the message center due to this electronic issue. When the issues are acting up I hear an intense clicking under the dash on the passenger side. Do you know anything of what could be wrong under there? Could it be I have to rewire something?

Thanks for response
Wes

There are at least four circuit breakers in that area that automatically reset. The clicking might be the sound of them resetting. One is for HVAC, one for reserve accessory power (RAP), another for the rear window de-fogger, the other is for the amp. Since you say the radio locks out I would try unplugging the radio and/or amp. to see if the draw goes away.

This is very helpful, me and my friends aren't nearly as good with electronics in the car, so my question is could any of those 3 things cause the electronics to "freak out"? When this clicking occurs, the radio locks, and I get a security message and a "service vehicle soon" message. I believe this is because the electronics on the car are jumping around all over the place. The battery gauge on the dash jumps from 12v to 0v over and over as well. Could the clicking cause all this?


Thanks,
Wes

I would say you have a short someplace causing the breaker to trip, most likely the radio the amp. Or wiring to one of them shorting to ground.

Could a short only happen at certain times? Sorry for so many questions, I am trying to figure this out. When I have the battery disconnected for at least an hour everything appears to be fine, including the radio. However, if I leave the battery connected for at least 2 hours things begin to freak again. Radio locks, clicking all in dash, even headlights flicker if it's bad enough. Does this make sense with a short in radio or amp? Thanks a ton...


Wes

That don't sound like a Radio/Amp type of issue. i am not sure if you have tried to disconnect the BCM and plug the connectors back in a few times. This is with the battery disconnected. It could be a bad connection between the connectors and the BCM. Could be a bad BCM.

Not sure about any type of Auto resetting fuses on the car. Only clicking that I know of would be related to Relays. That is another area that could be bad. The RAP relay could be going bad and when the BCM is telling the relay to turn off it could be that it don't. Again could be related to something bad in the BCM.

Before replacing the BCM, Maybe do the take battery cable off battery. Disconnect the BCM a few times doing the Plug in and take out method. Then to be safe you could try to disconnect and reconnect the Relays in the car as well. While doing this, Look for signs of burnt pins or pins that are black or not normal in color. Connect the battery back up and see what happens. If the issue is still present. it could be BCM.

I am sure it isn't an issue but your DEI alarm/Remote start should have a Valet Button to put your car in Valet mode. I would set that to Valet and see if there is a problem with the Alarm. I don't think it is the problem. If you can't find a valet button or if you feel that isn't going to help, you could always take the fuse out going to the alarm. This will make it so all options for the alarm won't work. With it in Valet mode you can still pop your trunk and lock and unlock your car doors with the remote. Again I don't think it is the issue but for testing reasons I would add that to something to try.

I agree with the BCM possibility after hearing of the added symptoms, however the same symptoms occur when the battery is very low or there is an internal short in the battery itself. I've heard of brand new batteries giving the same syptoms when they were defective. You might want to try swapping out the battery with a known good one and see what happens.

FYI...Here's a link to a thread discussing one of the auto resetting circuit breakers I'm referring to: https://montecarloforum.com/forum/fw...breaker-33233/